Externally programable magnetic valve assembly and controller

ABSTRACT

An externally programmable shunt valve assembly that includes a motor having a rotor that is operable in response to an externally applied magnetic field and configured to increase or decrease the working pressure of the shunt valve assembly. The motor may further include a position sensing mechanism that allows a position of the rotor, and associated pressure setting of the valve, to be determined using an external magnetic sensor. In certain examples the motor further includes a mechanical brake that is magnetically operable between a locked position and an unlocked position and which, in the locked position, prevents rotation of the rotor.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/675,497, filed Aug. 11, 2017, and titled “EXTERNALLY PROGRAMABLEMAGNETIC VALVE ASSEMBLY AND CONTROLLER,” which claims the benefit under35 U.S.C. § 119(e) and PCT Article 8 of co-pending U.S. ProvisionalApplication No. 62/374,046 filed on Aug. 12, 2016, and titled“EXTERNALLY PROGRAMMABLE MAGNETIC VALVE ASSEMBLY AND CONTROLLER,” whichis herein incorporated by reference in its entirety.

BACKGROUND

Hydrocephalus is a condition associated with ventricular enlargementcaused by net accumulation of fluid in the ventricles of the brain.Non-communicating hydrocephalus is hydrocephalus associated with anobstruction in the ventricular system and is generally characterized byincreased cerebrospinal fluid (CSF) pressure. In contrast, communicatinghydrocephalus is hydrocephalus associated with obstructive lesionswithin the subarachnoid space. Normal Pressure Hydrocephalus (NPH), aform of communicating hydrocephalus, primarily occurs in persons over 60years of age and is characterized by CSF at nominally normal pressure.Classic symptoms of NPH include gait disturbance, incontinence anddementia. In summary, NPH presents as an enlargement of the ventricleswith a virtually normal CSF pressure.

The objective in the treatment of hydrocephalus is to reduce theventricular pressure so that ventricular size returns to a normal level.Hydrocephalus is often treated by implanting into the brain a shunt thatdrains excess CSF from the ventricles or from the lumbar thecal space(in communicating hydrocephalus). Such shunts are termedventriculoatrial (VA) when they divert fluid from the ventricle to theatrium, or ventriculoperitoneal (VP) when fluid is diverted from theventricle to the peritoneum, or lumboperitoneal (LP) when CSF isdiverted from the lumbar region to the peritoneum. These shunts aregenerally comprised of a cerebral catheter (for ventricular shunts)inserted through the brain into the ventricle or a lumbar catheter (forlumbar shunts) inserted through a needle into the lumbar thecal spaceand a one-way valve system that drains fluid from the ventricle into areservoir of the body, such as the jugular vein (ventricular shunts) orthe peritoneal cavity (ventricular or lumbar shunts).

U.S. Pat. No. 4,595,390 describes a shunt that has a spherical sapphireball biased against a conical valve seat by stainless steel spring. Thepressure of the CSF pushes against the sapphire ball and spring in thedirection tending to raise the ball from the seat. When the pressuredifference across the valve exceeds a so-called “popping” or openingpressure, the ball rises from the seat to allow CSF to flow through thevalve and thereby vent CSF. U.S. Pat. No. 4,595,390 further describes anexternally programmable shunt valve that allows the pressure setting ofthe valve to be varied by applying a transmitter that emits a magneticsignal over the head of the patient over the location of the implantedshunt. Use of an external programmer with a magnetic transmitter allowsthe pressure setting of the valve to be adjusted non-invasivelyaccording to the size of the ventricles, the CSF pressure and thetreatment objectives.

U.S. Pat. No. 4,615,691 describes examples of a magnetic stepping motorthat can be used with the shunt valve of U.S. Pat. No. 4,595,390, forexample.

Although magnetically adjustable shunts allow the pressure of animplanted shunt to be adjusted externally, these existing shunts havesome limitations. For example, when a patient with an implantedmagnetically adjustable shunt valve is within proximity of a strongmagnet or strong magnetic field, such as a magnetic resonance imaging(MRI) device, the pressure setting of the valve can change. In addition,verification of the pressure setting of existing magnetic valves canrequire use of a radiopaque marker on the valve that is detected usingan X-ray taken of the location where the valve is implanted. Also, someprogrammers utilized to adjust the pressure setting of an implantedvalve are relatively large and heavy and require a connection to a walloutlet.

It would therefore be desirable to design improved ventricular andlumbar shunts, as well as an improved programmer to adjust the shunts.

SUMMARY OF THE INVENTION

Aspects and embodiments are directed to an externally programmable valveassembly comprising a magnetic motor that is configured to increase ordecrease the pressure setting of the valve either continuously or infinite increments. The valve assembly may be adapted for implantationinto a patient to drain fluid from an organ or body cavity of thepatient. In these embodiments, the valve assembly includes an inlet portadapted for fluid connection (either during manufacture or by thesurgeon during surgery) to one end of a catheter. The second end of thecatheter is inserted into the organ or body cavity to be drained offluid. The valve assembly further includes an outlet port adapted forfluid connection to an end of a drainage catheter. The other end of thedrainage catheter can be inserted into a suitable body cavity, such as avein or the peritoneal cavity, or into a drainage reservoir external tothe body, such as a bag. Examples of organs and body cavities that canbe drained using the valve assembly of the invention include withoutlimitation the eye, cerebral ventricle, peritoneal cavity, pericardialsac, uterus (in pregnancy), and pleural cavity. In particular, the valveassembly may be adapted for implantation into a patient suffering fromhydrocephalus. In such embodiments, the inlet port is adapted for fluidconnection to a first end of an inflow catheter (i.e. an intracerebralor intrathecal catheter) and the outlet port is adapted for fluidconnection to a first end of a drainage catheter. When implanted in thepatient, the second end of the intracerebral catheter is inserted in aventricle or lumbar intrathecal space of the patient and the second endof the drainage catheter is inserted into a suitable body reservoir ofthe patient, such as the jugular vein or the peritoneal cavity. Thus,when implanted in the patient, this device provides fluid communicationbetween the ventricle or lumbar region of the patient and the bodyreservoir of the subject, allowing cerebrospinal fluid to flow from theventricle or lumbar region through the valve casing to the bodyreservoir when the intraventricular or CSF pressure exceeds the openingpressure of the valve assembly. The patient may suffer fromhydrocephalus with increased intracranial pressure, or may suffer fromnormal pressure hydrocephalus. The removal of CSF from the ventricle orlumbar space reduces the intraventricular pressure.

Further aspects and embodiments are directed to methods of determiningthe pressure setting of an implanted valve assembly, and adjusting thepressure setting of the valve assembly following implantation into apatient. As discussed in more detail below, according to certainembodiments, adjustment of the pressure setting of the valve may beaccomplished via displacement of a magnetically actuated rotor in thevalve assembly, resulting in a change in the tension of a springproviding a biasing force against the valve element. The rotor willrotate within the rotor casing responsive to an applied externalmagnetic field.

As discussed in more detail below, certain aspects and embodiments aredirected to a magnetically operable motor that is suitable forincorporation into an implantable valve assembly. The magnetic motorassembly includes a stator having a plurality of stator lobes, and arotor that includes a plurality of magnetic poles and which isconfigured to rotate about the stator. An externally applied magneticfield (from outside the body into which the valve assembly is implanted)is used to magnetize the stator so as to cause rotation of the rotor, asdiscussed further below. The magnetically operable motor has theadvantage of allowing mechanical movement within the implantable valveassembly to alter the pressure setting of the valve, avoiding the needfor physical connection to the valve assembly from outside the body orthe use of implanted batteries. Additionally, as discussed furtherbelow, embodiments of the magnetic motor assembly are configured to behighly resistant to any influence from external strong magnetic fieldsthat are not specifically associated with desired control of the motor,such as fields generated by MRI or nuclear magnetic resonance (NMR)devices. Further, certain embodiments of the magnetic motor include amechanism by which an individual, for example, a doctor, can view thecurrent pressure setting of the valve in which the magnetic motor isused, without requiring the use of an X-ray or other imaging technique.

Certain aspects also include a method of decreasing ventricular size ina patient in need thereof, including surgically implanting the valveassembly into the patient, and setting the opening pressure of the valveto a pressure that is less than the ventricular pressure prior toimplantation of the valve. Alternatively, the opening pressure of theimplanted valve assembly may be set to a pressure that is higher thanthe ventricular pressure, such that the ventricular size may beincreased in a patient in need thereof.

According to one embodiment a surgically-implantable shunt valveassembly comprises a housing, an exterior of the housing being formed ofa physiologically-compatible material, and a magnetically operable motordisposed within the housing, the magnetically operable motor including astator and a rotor configured to rotate relative to the statorresponsive to a changing magnetic polarity of the stator induced by anexternal magnetic field, the rotor including a rotor casing and aplurality of rotor permanent magnet elements disposed in a ring withinthe rotor casing and arranged with alternating magnetic polarities,rotation of the rotor relative to the stator producing a selectedpressure setting of the shunt valve assembly. The shunt valve assemblyfurther comprises an inlet port positioned between the rotor casing andan exterior of the housing, the inlet port terminating at its rotorcasing end in a valve seat, a spring, a valve element biased against thevalve seat by the spring, the valve element and the valve seat togetherforming an aperture, and an outlet port positioned between the rotorcasing and the exterior of the housing, the shunt valve assemblyconfigured such that the aperture opens when a pressure of the fluid inthe inlet port exceeds the selected pressure setting of the shunt valveassembly so as to vent fluid through the aperture into the outlet port.

Another embodiment is directed to a system comprising an externallyprogrammable surgically-implantable shunt valve assembly, anon-implantable transmitter head, and a control device coupled to thetransmitter head. The surgically-implantable shunt valve assembly mayinclude a housing having an exterior formed of a physiologicallycompatible material, a magnetically operable motor disposed within thehousing, the magnetically operable motor including a stator and a rotorconfigured to rotate relative to the stator responsive to a changingmagnetic polarity of the stator induced by an external magnetic field,the rotor including a rotor casing and a plurality of rotor permanentmagnet elements disposed in a ring within the rotor casing and arrangedwith alternating magnetic polarities, a number of the rotor permanentmagnet elements being such that radially opposing ones of the pluralityof rotor permanent magnet elements have the same magnetic polarity,rotation of the rotor relative to the stator producing a selectedpressure setting of the shunt valve assembly, an inlet port positionedbetween the rotor casing and an exterior of the housing, the inlet portterminating at its rotor casing end in a valve seat, a spring, a valveelement biased against the valve seat by the spring, the valve elementand the valve seat together forming an aperture, and an outlet portpositioned between the rotor casing and the exterior of the housing, theshunt valve assembly configured such that the aperture opens when apressure of the fluid in the inlet port exceeds the selected pressuresetting of the shunt valve assembly so as to vent fluid through theaperture into the outlet port. The non-implantable transmitter head mayinclude a magnet assembly configured to produce the external magneticfield to induce the rotation of the rotor relative to the stator. Thecontrol device may be configured to provide a signal to the transmitterhead to control the transmitter head to produce the external magneticfield so as to set the pressure setting of the shunt valve assembly tothe selected pressure setting.

Another embodiment is directed to a surgically-implantable valveincluding a magnetic motor for adjusting a pressure setting of thevalve, the magnetic motor being physically isolated from electricalpower sources and powered by an external magnetic field applied fromoutside the valve. The magnetic motor may comprise a rotor including acircular rotor casing and a plurality of permanent rotor magnetsdisposed in a ring within the rotor casing and arranged with alternatingmagnetic polarities, the rotor casing configured to rotate about acentral axis of rotation, and a stator composed of a magnetically softand permeable material shaped as opposing circular stator discs andpositioned with respect to each of four quadrants underneath the rotormagnets so that when magnetized under the influence of the externalfield the stator strengthens and orients a local magnetic field in itsvicinity so as to cause incremental movement of the rotor about thecentral axis of rotation. The number of the permanent rotor magnets maybe such that radially opposing ones of the plurality of permanent rotormagnets have either the same or opposite magnetic polarity.

According to another embodiment a surgically-implantable shunt valveassembly comprises a spring, a valve element biased against a valve seatby the spring, the valve element and the valve seat together forming anaperture through which fluid is shunted by the valve, and a magneticmotor for adjusting a pressure setting of the valve, the magnetic motorbeing physically isolated from electrical power sources and powered byan external magnetic field applied from outside the valve assembly. Themagnetic motor may include a rotor having a rotor casing, a plurality ofpermanent rotor magnets disposed in a ring within the rotor casing andarranged with alternating magnetic polarities, and a cam that engagesthe spring, the rotor being configured to rotate about a central axis ofrotation, and a stator composed of a magnetically soft and permeablematerial and positioned below the rotor so that when magnetized underthe influence of the external field the stator strengthens and orients alocal magnetic field in its vicinity so as to cause rotation of therotor about the central axis of rotation, the rotation of the rotorcausing rotation of the cam that adjust a tension of the spring againstthe valve element and thereby adjusts the pressure setting of the shuntvalve assembly.

According to another embodiment a surgically-implantable shunt valveassembly comprises a spring, a valve element biased against a valve seatby the spring, the valve element and the valve seat together forming anaperture through which fluid is shunted by the valve, and a magneticmotor for adjusting a pressure setting of the valve, the magnetic motorbeing physically isolated from electrical power sources and powered byan external magnetic field applied from outside the valve assembly. Themagnetic motor may include a rotor having a rotor casing, a plurality ofpermanent rotor magnets disposed in a ring within the rotor casing andarranged with alternating magnetic polarities, and a cam that engagesthe spring, the rotor being configured to rotate about a central axis ofrotation, a stator composed of a magnetically soft and permeablematerial and positioned below the rotor so that when magnetized underthe influence of the external field the stator strengthens and orients alocal magnetic field in its vicinity so as to cause rotation of therotor about the central axis of rotation, the rotation of the rotorcausing rotation of the cam that adjust a tension of the spring againstthe valve element and thereby adjusts the pressure setting of the shuntvalve assembly, and a mechanical brake magnetically operable between alocked position and an unlocked position and configured, in the lockedposition, to prevent rotation of the rotor.

Another embodiment is directed to a surgically-implantable valveincluding a magnetic motor for adjusting a pressure setting of thevalve, the magnetic motor being isolated physically from electricalpower sources and powered by the influence of an external magnetic fieldapplied from outside the valve, the magnetic motor comprising a rotorincluding a circular rotor casing and a plurality of permanent rotormagnets disposed in a ring within the rotor casing and arranged withalternating magnetic polarities, the rotor casing configured to rotateabout a central axis of rotation, and an X-shaped stator composed of amagnetically soft and permeable material shaped and positioned withrespect to the rotor such that when magnetized under the influence ofthe external field, the stator strengthens and orients a local magneticfield in its vicinity so as to cause incremental movement of the rotorabout the central axis of rotation. The number of the permanent rotormagnets may be such that radially opposing ones of the plurality ofpermanent rotor magnets have either the same or opposite magneticpolarity.

According to another aspect, a method of adjusting a working (operating)pressure of a shunt valve assembly implanted in a patient in needthereof, comprises applying an external magnetic field in proximity tothe implanted shunt valve assembly and exterior to the patient.

According to one embodiment, a method of decreasing ventricular size ina patient in need thereof comprises implanting in the patient a shuntvalve assembly, and setting the selected pressure of the valve assemblyto a pressure that is less than a ventricular pressure of the patientprior to implantation of the valve.

According to another embodiment, a method of treating a patientsuffering from hydrocephalus comprises implanting in the patient a shuntvalve assembly, and setting the selected pressure of the shunt valveassembly to a pressure that is less than a ventricular pressure of thepatient.

In another embodiment, a method of increasing ventricular size in apatient in need thereof comprises implanting in the patient a shuntvalve assembly, and setting the selected pressure of the shunt valveassembly to a pressure that is greater than a ventricular pressure ofthe patient.

During the course of treatment, it is anticipated that increasing ordecreasing the selected operating pressure of the valve will be requiredto be performed by the clinician to effectively manage the patient'scondition. However, during use, the valve will be exposed toenvironmental magnetic fields that may potentially change the operatingpressure of the valve. Aspects and embodiments provide a valve mechanismdesign that facilitates adjusting the valve mechanism using a magneticfield produced by the programmer while resisting adjustment byextraneous environmental magnetic fields.

Further aspects and embodiments are directed to a kit for setting apressure in a surgically-implantable shunt valve. In some embodiments,the kit comprises a surgically-implantable shunt valve assembly having amagnetically operable motor configured to provide a selected pressuresetting of the shunt valve assembly; a pressure reader configured toprovide a pressure reading of the surgically-implantable shunt valveassembly; and a programmer having at least one programmer magnet, the atleast one programmer magnet being selectively movable and configured toactuate the magnetically operable motor to allow a user to adjust thepressure setting of the surgically-implantable shunt valve assembly tomatch a pressure setpoint of the programmer.

In some embodiments, the pressure reader further comprises an arrow onan upper surface of the pressure reader.

In some embodiments, the pressure reader further comprises a concavesurface defined on a lower surface of the pressure reader.

In some embodiments, the programmer further comprises a user interface.

In some embodiments, the programmer further comprises a first button toincrease the pressure setpoint and a second button to decrease thepressure setpoint.

In some embodiments, the programmer further comprises a wheel beingrotatable in a first direction to increase the pressure setpoint, andthe wheel being rotatable in a second direction to decrease the pressuresetpoint.

In some embodiments, the programmer further comprises a cavity on alower surface of the programmer.

In some embodiments, the pressure reader includes one of a magnet and aHall sensor.

In some embodiments, the surgically-implantable shunt valve assemblycomprises a housing, an exterior of the housing being formed of aphysiologically-compatible material; the magnetically operable motordisposed within the housing, the magnetically operable motor including astator and a rotor configured to rotate relative to the statorresponsive to a changing magnetic polarity of the stator induced by anexternal magnetic field, the rotor including a rotor casing and aplurality of rotor permanent magnet elements disposed in a ring withinthe rotor casing and arranged with alternating magnetic polarities,rotation of the rotor relative to the stator producing the selectedpressure setting of the shunt valve assembly; an inlet port positionedbetween the rotor casing and an exterior of the housing, the inlet portterminating at its rotor casing end in a valve seat; a spring; a valveelement biased against the valve seat by the spring, the valve elementand the valve seat together forming an aperture; and an outlet portpositioned between the rotor casing and the exterior of the housing, theshunt valve assembly configured such that the aperture opens when apressure of the fluid in the inlet port exceeds the selected pressuresetting of the shunt valve assembly so as to vent fluid through theaperture into the outlet port.

In some embodiments, the surgically-implantable shunt valve assemblyincludes a rotor marker attached to the rotor such that the rotor markerrotates with the rotor and a housing marker fixedly attached to thehousing, wherein a position of the rotor marker relative to the housingmarker is indicative of the pressure setting of thesurgically-implantable shunt valve assembly.

In some embodiments, the rotor marker comprises tantalum and the housingmarker comprises tantalum.

In some embodiments, the magnetically operable motor is a stepper motorhaving a rotatable rotor, and wherein the surgically-implantable shuntvalve assembly further comprises a mechanical brake mechanismmagnetically operable between a locked position and an unlocked positionand configured, in the locked position, to prevent rotation of therotor; and an indicator magnet assembly configured to allow an externalsensor to magnetically determine a position of the rotor and thereby todetermine the pressure setting.

Still other aspects, embodiments, and advantages of these exemplaryaspects and embodiments are discussed in detail below. Embodimentsdisclosed herein may be combined with other embodiments in any mannerconsistent with at least one of the principles disclosed herein, andreferences to “an embodiment,” “some embodiments,” “an alternateembodiment,” “various embodiments,” “one embodiment” or the like are notnecessarily mutually exclusive and are intended to indicate that aparticular feature, structure, or characteristic described may beincluded in at least one embodiment. The appearances of such termsherein are not necessarily all referring to the same embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects of at least one embodiment are discussed below withreference to the accompanying drawings in which like referencecharacters refer to the same parts throughout the different views. Forpurposes of clarity, not every component may be labeled in everydrawing. The drawings are not necessarily to scale, emphasis insteadbeing placed upon illustrating the principles of the invention. Thedrawings are included to provide illustration and a furtherunderstanding of the various aspects and embodiments, and areincorporated in and constitute a part of this specification, but are notintended as a definition of the limits of the invention. In thedrawings:

FIG. 1A is a plan view of one example of an implantable valve assembly,showing a top view, according to aspects of the invention;

FIG. 1B is a cross-sectional view of the valve assembly of FIG. 1A;

FIG. 2 is a three-dimensional drawing of one example of an implantablevalve according to aspects of the present invention;

FIG. 3A is a diagram showing a plan view of one example of animplantable valve, corresponding to the example shown in FIG. 2,according to aspects of the invention;

FIG. 3B is a side view of the example of the implantable valve shown inFIG. 3A;

FIG. 4A is a cross-sectional view of one example of the valve of FIGS. 2and 3A-B taken along line A-A in FIG. 3A;

FIG. 4B is a cross-sectional view of the example of the valve of FIGS. 2and 3A-B taken along line B-B in FIG. 3A;

FIG. 4C is a cross-sectional view of the example of the valve of FIGS. 2and 3A-B taken along line C-C in FIG. 3A;

FIG. 5 is a three-dimensional cross-sectional view of an example of thevalve of FIGS. 2 and 3A-B, according to aspects of the invention;

FIG. 6A is a diagram showing an enlarged view of a portion of the valveof FIG. 5, with the cam shown in a position of minimum tension againstthe biasing spring, according to aspects of the invention;

FIG. 6B is a diagram showing another view of a portion of the valve ofFIG. 5, with the cam shown in a position of minimum tension against thebiasing spring, according to aspects of the invention;

FIG. 6C is a diagram showing an enlarged view of a portion of the valveof FIG. 5, with the cam shown in a position of maximum tension againstthe biasing spring, according to aspects of the invention;

FIG. 6D is a diagram showing an enlarged view of a portion of the valveof FIG. 5, showing an example of the spring biased against the valveelement and the cam, according to aspects of the invention;

FIG. 7A is a diagram showing an example of a flat spring according toaspects of the present invention;

FIG. 7B is a partial perspective view showing an example of the flatspring of FIG. 7A installed in a valve according to aspects of thepresent invention;

FIG. 8A is a diagram showing an example of a u-shaped spring accordingto aspects of the present invention;

FIG. 8B is a diagram showing the u-shaped spring of FIG. 8A installed ina programmable valve, according to aspects of the present invention;

FIG. 8C is a diagram showing a portion of the programmable valve of FIG.8B when the programmable valve is set at the lowest pressure setting;

FIG. 8D is a diagram showing a portion of the programmable valve of FIG.8B when the programmable valve is set at the highest pressure setting;

FIG. 9A is a diagram illustrating another example of a spring accordingto aspects of the present invention;

FIG. 9B is a diagram showing the spring of FIG. 9A engaging a valveelement, according to aspects of the present invention;

FIG. 10A is a schematic diagram of one example of a rotor for use inembodiments of a magnetically-operable implantable valve according toaspects of the present invention, showing the rotor positioned for aminimum pressure setting of the valve;

FIG. 10B is a schematic diagram of the rotor of FIG. 10A showing therotor positioned for a maximum pressure setting of the valve;

FIG. 11A is a diagram of an implanted valve and an example of anexternal valve programmer with a control and display, according toaspects of the invention;

FIG. 11B is a diagram of an implanted device and another example of anexternal programmer according to aspects of the invention.

FIG. 11C is a diagram of an implanted valve and an example of a pressurereading device for reading the pressure setting of the valve, accordingto aspects of the invention;

FIG. 12 is a block diagram of one example of an external control devicethat can be used in combination with an implantable programmable valveaccording to aspects of the invention;

FIG. 13 is a diagram showing operation of one example of a magneticmotor including twelve rotor magnet elements and controlled by acontroller including a plurality of electromagnets according to aspectsof the invention;

FIG. 14 is a three-dimensional partial cross-sectional view of oneexample of a magnetic motor according to aspects of the invention;

FIG. 15 is a table showing an example of a sequence of energizing theelectromagnets of the controller of FIG. 13 to effect clockwise rotationof the magnetic rotor, according to aspects of the invention;

FIGS. 16A-H are diagrams showing the magnetic polarity of the stator andmovement of the rotor responsive to the energizing sequence of FIG. 15;

FIG. 17 is a table showing an example of a sequence of energizing theelectromagnets of the controller of FIG. 13 to effect counter-clockwiserotation of the magnetic rotor, according to aspects of the invention;

FIGS. 18A-H are diagrams showing the magnetic polarity of the stator andmovement of the rotor responsive to the energizing sequence of FIG. 17;

FIG. 19 is a block diagram of another example of an external valveprogrammer that can be used with embodiments of the implantable valveassembly according to aspects of the invention;

FIG. 20A is a diagram of one example of a permanent magnet assembly forthe external valve programmer of FIG. 19, according to aspects of theinvention;

FIG. 20B is a diagram of another example of a permanent magnet assemblyfor the external valve programmer of FIG. 19, according to aspects ofthe invention;

FIGS. 21A-E are diagrams illustrating an example of the changingmagnetic polarity of the stator and movement of the rotor under controlof an example of an external valve programmer incorporating thepermanent magnet assembly of FIG. 20A, according to aspects of theinvention;

FIG. 22 is a flow diagram illustrating an example of the changingpolarity of the stator and movement of the rotor as exemplified in FIGS.21A-E representative of one full rotation of an external permanentmagnet valve programmer, according to aspects of the invention;

FIG. 23A is a diagram showing a top plan view of one example of a valveprogrammer according to aspects of the present invention;

FIG. 23B is a diagram showing a bottom plan view of the valve programmerof FIG. 23A;

FIG. 23C is a diagram showing an end view of the valve programmer ofFIGS. 23A-B;

FIG. 23D is a diagram showing a perspective view of the valve programmerof FIGS. 23A-C;

FIG. 23E is a diagram showing a top plan view of another example of avalve programmer according to aspects of the present invention;

FIG. 24 is a flow diagram for one example of a method of operating thevalve programmer of FIGS. 23A-D to program the pressure setting of animplantable valve according to aspects of the present invention;

FIGS. 25A-C are diagrams showing examples of different configurations ofstators in combination with a twelve-magnet rotor, according to aspectsof the invention;

FIGS. 26A-C are diagrams showing further examples of stators incombination with a twelve-magnet rotor, according to aspects of theinvention;

FIG. 27 is a diagram of one example of a rotor including referencemagnet elements according to aspects of the invention;

FIGS. 28A-C are diagrams showing further examples of a motor assemblyincluding reference magnet elements according to aspects of the presentinvention;

FIG. 29 is a block diagram of one example of an external valveprogrammer including a magnet sensor to detect the reference magnetelements, according to aspects of the invention;

FIG. 30A is a perspective view of one example of a pressure readeraccording to aspects of the present invention;

FIG. 30B is a top plan view of the pressure reader of FIG. 30A;

FIG. 31 is a flow diagram of one example of a method of operating apressure reader to read the pressure setting of an implanted valveaccording to aspects of the present invention;

FIG. 32 is a diagram showing a cross-sectional view of another exampleof a motor including reference or position-indicating magnet elementsaccording to aspects of the invention;

FIG. 33 is a partial cross-sectional three-dimensional view of oneexample of a programmable valve including a brake mechanism according toaspects of the invention;

FIG. 34 is a schematic diagram showing certain aspects of an example ofthe brake mechanism according to aspects of the invention;

FIG. 35 is a diagram illustrating another example of a permanent magnetassembly for the external valve programmer of FIG. 19 incorporating amagnetic brake controller mechanism, according to aspects of theinvention;

FIG. 36 is a flow diagram of one example of a method of programming animplanted programmable valve according to aspects of the invention;

FIG. 37A is a cross-sectional view of one example of the programmablevalve of FIG. 33 according to aspects of the invention showing the brakein the locked position;

FIG. 37B is a corresponding cross-sectional view showing the brake inthe unlocked position;

FIG. 38 is a diagram illustrating another example of a permanent magnetassembly for the external valve programmer of FIG. 19, according toaspects of the invention;

FIG. 39 is a flow diagram of another example of a method of programmingan implanted programmable valve according to aspects of the invention;

FIG. 40 is diagram showing another example of the programmable valveincluding a brake mechanism according to aspects of the invention;

FIG. 41 is a partial cross-sectional perspective view of another exampleof programmable valve including a magnetic motor incorporating a brakemechanism according to aspects of the invention;

FIG. 42 is a plan view of the example of the valve shown in FIG. 41;

FIG. 43 is a plan view of another example of a motor assembly of a valvesimilar to that shown in FIG. 41, according to aspects of the invention;

FIG. 44A is a cross-sectional view of the example of the valve shown inFIG. 42 taken along line A-A in FIG. 42;

FIG. 44B is a cross-sectional view of the example of the valve shown inFIG. 42 taken along line B-B in FIG. 42;

FIG. 45 is a diagram showing another example of a brake spring accordingto aspects of the invention;

FIG. 46A is a schematic cross-sectional view of the example of the valveshown in FIG. 42, showing the brake in the locked position;

FIG. 46B is a corresponding schematic cross-sectional view of theexample of the valve shown in FIG. 42, showing the brake in the unlockedposition;

FIG. 47A is a plan view of another example of a programmable valveaccording to aspects of the invention;

FIG. 47B is a cross-sectional view of the programmable valve shown inFIG. 47A taken along line A-A in FIG. 47A; and

FIG. 48 shows another example of a programmable valve incorporating abrake mechanism according to aspects of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Aspects and embodiments are directed to a valve assembly thatincorporates a magnetic motor configured to increase or decrease theworking pressure of the valve either continuously or in finiteincrements. As discussed in more detail below, by magneticallyrepositioning a rotor within a casing of the valve assembly, the openingpressure of the valve element may be adjusted, thereby increasing ordecreasing the flow of fluid through the valve assembly. Certainembodiments of the valve assembly are adapted for implantation into apatient suffering from hydrocephalus, and may be used to drain CSF.

In particular, certain aspects and embodiments provide an externally andmagnetically programmable valve incorporating a magnetic motor andexternal controller having the following features. The valve isconfigured such that an operator, for example, a doctor, is able toadjust the valve either continuously or in small pressure increments(e.g., increments of approximately 10 mm H₂O) up to a pressure of about200 mm H₂O, and the valve has a “closed” setting of approximately300-400 mm H₂O. The valve is highly resistant to non-programmingexternal magnetic fields in the environment, such as the magnetic fieldof a 3 Tesla MRI, for example, such that the pressure setting of thevalve does not change appreciably when the patient is in the proximityof an MRI machine or other instrument (other than the valve controller)that generates a magnetic field. In certain embodiments, the valve isconfigured such that the operator (e.g., the doctor) is able to verifythe pressure setting of the valve with a method other than X-Rays.Furthermore, according to certain embodiments the valve controller issmall, very portable, and battery-operated. These and other features andconfigurations of the valve according to various embodiments arediscussed in more detail below.

Referring to FIGS. 1A and 1B, there is illustrated one example of animplantable shunt valve assembly 100 including two valves 200 and 300separated by a pumping chamber 110. In one example, a ventricularcatheter 120 can be connected to an inlet 130 of the valve assembly 100,and a drainage catheter can be attached to a connector 140 and connectedto an outlet 150 of the valve assembly. Depression of the pumpingchamber 110 pumps fluid through the valve 300 toward the outlet 150 andthe drainage catheter. Releasing the pumping chamber after it has beendepressed pumps fluid through the valve 200. The valve 200 is anexternally programmable valve including a magnetic motor, as discussedin more detail below. The second valve 300 can be a check valve, forexample. In this case, after passing through the programmable valve 200,fluid flows through the check valve 300 before exiting into the drainagecatheter. In one example the programmable valve 200 operates to keep thevalve assembly 100 closed until the fluid pressure rises to apredetermined pressure setting of the valve. Generally, the check valve300 may be set at a low pressure, allowing the pressure setting of theprogrammable valve 200 including the magnetic motor to control the flowof fluid through the valve assembly 100. In other examples, the secondvalve 300 can be a gravity-activated valve that allows the valveassembly 100 to automatically adjust in response to changes in CSFhydrostatic pressure that occur when the patient's posture changes(i.e., moving abruptly from a horizontal (recumbent) to a vertical(erect) position). In particular, to avoid the valve opening responsiveto these pressure changes, which could cause over-drainage of CSF, thevalve assembly 100 can include a gravity activated valve connected inseries with and on the outlet side of the programmable valve 200, asshown in FIGS. 1A and 1B, the gravity activated valve being configuredto open at higher pressures when the patient is substantially vertical.

Those skilled in the art will appreciate, given the benefit of thisdisclosure, that the length, size, and shape of various embodiments ofthe valve assembly 100 can be adjusted. Certain embodiments of the valveassembly 100 may further comprise a reservoir or pre-chamber orantechamber for sampling the fluid and/or injecting pharmaceuticalagents or dyes, power on/off devices, anti-siphon or other flowcompensating devices, and/or additional catheters. When included, thepre-chamber (not shown in FIGS. 1A and 1B) would be connected betweenthe inlet 130 and the programmable valve 200. According to certainembodiments, the valve assembly 100 may include a combination of thepumping chamber 110, a pre-chamber, the second valve 300 (which can be acheck valve or gravity-activated valve, for example), and optionally ananti-siphon device (not shown). In other embodiments, one or more ofthese components may be omitted. For example, the valve assembly 100 mayinclude the pumping chamber 110 and second valve 300, without apre-chamber, as shown in FIGS. 1A and 1B. The pumping chamber 110 mayalso or alternatively be omitted. In such embodiments, after the fluidpasses through the programmable valve 200, it flows through the secondvalve 300. Alternatively, the valve assembly 100 may include apre-chamber, with or without the pumping chamber 110 or the second valve300. The valve assembly 100 can be surgically implanted into a patientusing well-known procedures.

FIG. 2 illustrates a three-dimensional view of one example of animplantable magnetically programmable valve 200 according to certainaspects. FIGS. 3A and 3B illustrate external views of the implantablemagnetically programmable valve 200 of FIG. 2, according to certainembodiments. FIG. 3A is a plan view and FIG. 3B is an end view. Thevalve 200 includes a valve body 202 (also referred to as a housing) thathouses the components of the valve. The valve 200 includes an inlet port204 and an outlet port 206. The inlet port 204 may be connected to aproximal (or inflow) catheter, and the outlet port 206 may be connectedto a distal or outflow catheter. In the case of a valve assembly thatshunts CSF fluid, the proximal catheter may be the ventricular catheter120 or a lumbar catheter. In this case, the CSF fluid from the ventricleenters the ventricular catheter or lumbar catheter and enters the inletport 204 of the valve assembly 100. The distal catheter acts as thedrainage catheter connected to the connector 140 to direct fluid to aremote location of the body (such as the right atrium (VA shunting) ofthe heart or the peritoneal cavity (VP or LP shunting) for drainage.

The valve body 202 may include a top cap 202 a and a bottom cap 202 bthat mates with the top cap 202 a to form a sealed enclosure that issuitable for implantation into the human body. The “top” of the valve200 is the side of the device oriented to face up toward the patient'sscalp when implanted. The valve body 202 may be made from anyphysiologically compatible material. Non-limiting examples ofphysiologically compatible materials include polyethersulfone andsilicone. As will be appreciated by those skilled in the art, the valvebody 202 may have a variety of shapes and sizes, at least partiallydependent on the size, shape, and arrangement of components within thevalve 200.

Various aspects and features, and operation, of the valve 200, includingoperation of the magnetic motor, are discussed below with reference toFIGS. 2, 3A-B and 4A-D. FIG. 4A is a cross-sectional view of one exampleof the valve 200 taken along line A-A in FIG. 3A and showing certaincomponents of the magnetic motor. FIG. 4B is a three-dimensionalcross-sectional view of the example of the valve 200 of FIGS. 2 and3A-B, taken along line B-B in FIG. 3A and showing certain components ofthe magnetic motor. FIG. 4C is another cross-sectional view of theexample of the valve 200 of FIGS. 2 and 3A-B, taken along line C-C inFIG. 3B and showing certain components of the magnetic motor. FIG. 5 isanother cross-sectional view of the example of the valve 200 of FIGS. 2and 3A-B, taken along line A-A in FIG. 3A.

Referring to FIGS. 2, 3A-B, and 4A-C, according to certain embodiments,the valve 200 includes a valve element 208 biased against a valve seat210 by a spring 400. The spring 400 may comprise, for example, anextension spring, a compression spring, a helical or coiled spring, atorsional spring, a flat spring, a leaf spring, or a cantilever spring.Certain embodiments of the spring 400 are discussed in more detailbelow.

Fluid enters the valve 200 via the ventricular catheter, for example,and flows through the inlet port 204, which terminates at its casing endat the valve seat 210. The pressure of the fluid (e.g. CSF) pushesagainst the valve element 208 and the spring 400 in the directiontending to raise the valve element 208 from the valve seat 210. Surfacesof the valve element 208 and valve seat 210 together define an aperture,and the size or diameter of the aperture determines the rate and amountof fluid flow through the valve 200. The valve element 208 preferablyhas a diameter greater than the valve seat 210 such that when the valveelement 208 rests against the valve seat 210, the aperture issubstantially closed. The valve element 208 is placed on the inlet sideof the aperture and is biased against the circular periphery of theaperture, keeping it closed until the CSF pressure in the inlet chamberexceeds a preselected popping pressure. The term “popping pressure”refers to the opening pressure of the valve and is generally, a slightlyhigher pressure than the working pressure and is required to overcomeinertia when the ball has settled in to the seat. The term “workingpressure” can also be referred to as the “operating pressure” and is thepressure of the valve while fluid flows through the valve 200. Theclosing pressure is the pressure of the valve at which the flow of fluidthrough the valve stops.

The valve element 208 can be a sphere, a cone, a cylinder, or othersuitable shape. In the example illustrated in FIGS. 4C and 5, the valveelement 208 is a spherical ball. The spherical ball and/or the valveseat 210 can be made from any appropriate material including, forexample, synthetic ruby or sapphire. The valve seat 210 provides acomplementary surface, such as a frustoconical surface for a sphericalvalve element such that, in a closed position of the valve 200, seatingof the valve element 208 within the valve seat 210, results in a fluidtight seal. The pressure setting, for example, the opening pressure, ofsuch valves is adjusted by altering the biasing force of the valveelement 208 against the valve seat 210. In one example the valve element208 and valve seat 210 may be press-fit into the housing 202, and, oncethe initial pressure setting is reached, held in place by the friction.In one example of this configuration, the valve element 208 includes aruby ball, and the valve seat 210 is also made of ruby.

According to one embodiment, biasing of the spring 400 against the valveelement 208 is achieved using a magnetic motor that increases ordecreases the working pressure of the valve 200 either continuously orin finite increments. According to certain embodiments, the magneticmotor includes a stator 528 and a rotor 510 that rotates relative to thestator 528 responsive to an external magnetic control field. In oneexample, the rotor 510 rotates about a central axis of rotation 214.Configuration and operation of embodiments of the magnetic motor arediscussed in more detail below.

Referring to FIGS. 2, 4A-C, and 5, according to certain embodiments, therotor 510 includes a plurality of rotor magnet elements 512 arranged ina rotor casing 514. FIGS. 4C and 5 show the plurality of rotor magnetelements 512 arranged in a circle and disposed within the rotor casing514. Thus, the rotor casing 514 includes an approximately circularchannel 522 in which the rotor magnet elements 512 are contained. In oneexample, the rotor magnet elements 512 are permanent magnets, eachhaving a south pole and a north pole. The rotor magnet elements 512 arearranged approximately in a circle, as shown in FIG. 4C, withalternating polarity, such that, whether viewed from the top (as in FIG.4C) or bottom, the south and north poles alternate between every rotormagnet element. Thus, at any one angular position, the pole exposed onthe top surface of the element is opposite that of the one exposed onthe bottom surface. The rotor magnet elements 512 can be fixedly mountedto the rotor casing 514, which can act as a magnet guide to contain anddirect rotation of the rotor magnet elements 512. In FIGS. 2, 4C, and 5,the rotor magnet elements 512 are shown as circular disks; however it isto be appreciated that the rotor magnet elements 512 need not bedisk-shaped, and can have any shape, such as, but not limited to,oblong, square, rectangular, hexagonal, free-form, and the like. It ispreferable that all the rotor magnet elements 512 are either ofapproximately the same size or approximately the same magnetic strengtheven if their size varies to ensure smooth rotation of the rotor 510.According to one embodiment, the rotor 510 includes twelve rotor magnetelements 512 arranged in a circle, as shown in FIG. 4C. According toanother embodiment, the rotor 510 includes ten rotor magnet elements 512arranged in a circle, as discussed further below. In other examples therotor 510 may include other numbers of rotor magnet elements 512, andembodiments of the programmable valve disclosed herein are not limitedto including ten or twelve rotor magnet elements.

According to certain embodiments, in addition to the rotor magnetelements 512, the rotor 510 can further include one or more additionalreference magnet elements (also referred to as positioning magnets) 524,as shown in FIGS. 4A and 5. The reference magnet elements 524 can beread by a pressure reader as described herein, or the reference magnetelements 524 can be used as positioning magnets to orient an indicatormagnet, such as the indicator magnet 552 discussed below with referenceto FIG. 32. The reference magnet element(s) 524 can be placed on top ofone or more rotor magnet elements 512, and can be used to allow adoctor, for example, to determine a pressure setting of the valve 200using an external magnetic sensor, such as a Hall sensor, for example,without requiring X-rays or other imaging techniques, as discussedfurther below.

The rotor 510 is configured to rotate about the rotor axis 214responsive to an applied external magnetic field that acts upon thestator 528. The rotor 510 thus can further include bearing rings 516arranged adjacent an inner circumference of the rotor casing 514, asshown in FIGS. 4A and 4B, to allow rotation of the rotor casing 514. Thebearing rings 516 may be made of synthetic ruby, for example. In certainexamples the magnetic motor includes two bearing rings 516, namely anupper bearing ring and a lower bearing ring, as shown in FIGS. 4A and4B. However, in other examples the upper bearing ring may be omitted. Inthis case, the rotor 510 may tilt on the lower bearing ring 516 as itrotates. In certain examples, this tilting may be advantageous inincreasing resistance of the magnetic motor to adjustment by extraneousenvironmental magnetic fields. In other examples, the lower bearing ring516 may be made sufficiently wide to avoid any tilting of the rotor 510as it rotates on the bearing ring.

According to one embodiment, magnetic pulses from an external magneticfield are used to selectively magnetize the stator 528, which acts uponthe magnetic rotor and thereby controls movement of the rotor 510. Theexternal magnetic field may be produced, for example, by a magnetic coilor permanent magnet that is placed in proximity to the valve assembly,as discussed in more detail below. The stator 528 can be made of a softmagnetic material that can be selectively magnetized, and the magneticpolarity of which can be selectively controlled, by the application ofthe external magnetic field. For example, the stator 528 can be made ofa Nickel-Iron alloy, for example, having approximately 72-83% Nickel. Bycontrolling the magnetization and magnetic polarity of the stator 528,the rotor 510 can be made to rotate in a controlled manner as the rotormagnet elements 512 respond to the changing magnetization and magneticpolarity of the stator 528, as discussed further below.

The valve 200 is configured such that rotation of the rotor 510 controlsthe spring 400 to adjust the biasing of the valve element 208 againstthe valve seat 210, thereby adjusting the size of the aperture andcontrolling the flow of fluid through the valve 200. In one embodiment,the valve 200 includes a cam 212, which engages the spring 400, as shownin FIGS. 2, 4C, and 5. In the illustrated example, the cam 212 isintegrated with the rotor casing 514, thereby avoiding the need for aseparate cam element. In other embodiments; however, the cam can becoupled to the rotor 510 and positioned in contact with the spring 400such that rotation of the rotor 510 causes movement of the cam 212which, in turn, adjusts the tension of the spring 400 against the valveelement 208. For example, the cam 212 could be attached to the rotorcasing 514 via a central shaft 520, such that the rotor casing 514 andthe cam 212 can rotate together about the central axis 214. As usedherein the term “cam” refers either to a separate cam element that canbe attached to the rotor or to the rotor casing 514 acting as a cam, asin the illustrated examples in which the cam is integrated with therotor casing.

For certain applications of the valve assembly 100, such as thetreatment of hydrocephalus, for example, the pressure range of the valvemay be approximately 0-200 mm H₂O or 0-400 mm H₂O, for example, whichare very low pressure ranges. Furthermore, it may be desirable to makesmall pressure changes within the range. However, it may not bepracticable (due to manufacturing constraints, etc.) to produce a valveassembly in which the cam 212 is capable of making very minutemovements, for example, on the order of a few micrometers. Therefore, inorder to accommodate the low-pressure range and small incrementalchanges in pressure, a very soft spring may be required. Conventionally,in order to obtain a sufficiently soft spring, the spring 400 would bevery long. However, accommodating a very long, soft spring inside animplantable housing may pose challenges. Accordingly, aspects andembodiments are directed to spring configurations that produce a leveror “gear reduction” effect, such that reasonable (i.e., within standardmanufacturing capabilities) movements of the cam 212 may be translatedinto very small adjustments in low-pressure settings. In particular,certain embodiments include a cantilever spring configuration, as shownin FIG. 6A, for example.

FIGS. 6A, 6B, 6C, and 6D illustrate views of the portions of theprogrammable valve 200, showing the cam 212 and the spring 400 biasedagainst the valve element 208. FIGS. 6A and 6B show the cam 212 in theposition of minimum tension against the biasing spring 400, and FIG. 6Cshows the cam 212 in the position of maximum tension against the biasingspring 400. FIG. 6D shows an enlarged view of one example of the spring400. In FIG. 6D the spring 400 is shown with the valve element 208seated in the valve seat 210. In this example the spring 400 is acantilever spring and includes a first spring arm 410 that is in director indirect contact with the cam 212, and a cantilevered arm 420 that isbiased against the valve element 208. Both the first spring arm 410 andthe cantilevered arm 420 extend in the same direction from a fulcrum 430(or fixed attachment point of the spring 400). Thus, the cantileveredarm 420 has a fixed end at the fulcrum 430 and a free end 422 that restsagainst the valve element 208, as shown in FIGS. 6A and 6C. Similarly,the first spring arm 410 has a fixed end at the fulcrum 430 and a freeend that engages the cam 212. In certain examples the cantilevered arm420 may be longer than the spring arm 410. In the illustrated examplethe spring arm 410 is “bent”, including an inflection point 412. Thisconfiguration allows for a reduction in the overall size of the spring400 relative to examples in which the first spring arm is straight.Rotation of the cam 212 causes pressure against the spring arm 410 incontact with the cam, changing the tension in the spring 400. Thatpressure is spread and reduced through the spring structure, such thatresulting pressure applied against the valve element 208 by thecantilevered arm 420 can be very low, and in particular, can be within adesired range (e.g., 0-200 mm H₂O, as mentioned above), without placingdifficult or impracticable constraints on the rotational movement of thecam 212. By appropriately selecting the relative lengths of the two arms410 and 420, and the widths of each arm, the equivalent of a lever orgear reduction mechanism may be achieved. Thus, a sufficiently softspring to provide the low pressures (e.g., 0-200 mm H2O) needed forcertain applications may be achieved using a short, two-armed spring400, rather than a conventional long spring.

The spring 400 can have a variety of different shapes andconfigurations, not limited to the example shown in FIGS. 6A-D. Forexample, FIG. 7A and FIG. 7B show a flat spring 460. FIG. 7A shows theflat spring alone, and FIG. 7B shows the spring installed in a valve andbiased against the valve element 208. The flat spring 460 includes afirst spring arm 462 that is in direct or indirect contact with the cam212 and a cantilevered arm 464 that is biased against the valve element208. In this example, the cantilevered arm 464 includes a rounded endportion 464 a that rests against the valve element 208. Both the firstspring arm 462 and the cantilevered arm 464 are flat and extend from afulcrum 430. The cam 212 is not shown in FIG. 7B.

FIGS. 8A and 8B show an example of a u-shaped cantilevered spring 480.FIG. 8A shows the u-shaped spring 480 alone. FIG. 8B is a sectional viewof a portion of an example of the programmable valve 200 showing theu-shaped spring 480 installed in the valve 200. The u-shaped spring 480includes a first spring arm 482 that is in direct or indirect contactwith the cam 212 and a cantilevered arm 484 that is biased against thevalve element 208. The cantilevered arm 484 has a free end 486 thatrests against the valve element 208. The first spring arm 482 and thecantilevered arm 484 are connected by a u-shaped portion 483 that issupported by a post 488. In some embodiments, the u-shaped portion 483is spring biased around the post 488 so the u-shaped portion 483frictionally engages the post 488.

Similar to FIGS. 6B and 6C discussed above, FIGS. 8C and 8D showexamples of the u-shaped spring 480 positioned corresponding todifferent pressure settings of the programmable valve 200. FIG. 8C showsthe u-shaped spring 480 when the cam 212 is oriented such that theprogrammable valve 200 is set at the lowest pressure setting. FIG. 8Dshows the u-shaped spring 480 when the cam 212 is oriented such that theprogrammable valve 200 is set at the highest pressure setting.

FIG. 9A shows another example of a cantilevered spring 490 having afirst spring arm 492 that is configured to be in direct or indirectcontact with the cam 212 and a cantilevered spring arm 494 that isbiased against the valve element 208. The cantilevered spring arm 494has a free end 496 that rests against the valve element 208. In thisexample, the first spring arm 492 and the cantilevered spring arm 494are secured to a post 498, for example, by welding. FIG. 9B shows anexample of the spring 490 of FIG. 9A in a programmable valve 200. Thepost 498 is configured to rotate on two ruby bearings 491 and 493. Oneruby bearing 491 is positioned at an upper portion of the post 498 andthe second ruby bearing 493 is positioned at a lower portion of the post498. The ruby bearings 491, 493 allow the post 498 to pivot with respectto the valve body 202.

As will be appreciated by those skilled in the art, given the benefit ofthis disclosure, the spring 400 may have other configurations inaddition to those described above and shown in the drawings.

In certain examples as the cam 212 rotates, the force exerted againstthe spring 400 is adjusted in fine increments or continuously over arange from minimum force to maximum force. As shown in FIG. 6C, when thecam 212 is in the position in which the maximum pressure is exerted bythe cam 212 against the spring 400, the cantilevered arm 420 is movedtoward the valve element 208. Thus, the pressure setting of the valve200 is highest for this position of the cam 212. In one example,pressure exerted by the cam 212 against the spring 400, and thereforethe tension in the spring 400, increases with clockwise rotation of thecam 212, as indicated by arrow 216. However, those skilled in the artwill appreciate, given the benefit of this disclosure, that the rotor510, cam 212, and spring 400 may alternatively be configured such thatcounter-clockwise rotation of the rotor 510 increases the tension in thespring 400.

As described above, the valve element 208 and valve seat 210 form anaperture through which the fluid flows. The inlet port 204 can beoriented such that fluid enters the aperture (or, in other words, pushesagainst the valve element) in a direction perpendicular to a centralaxis of the rotor 510. The inlet port 204 can also be oriented such thatfluid enters the aperture (or pushes against the valve element) in adirection that is perpendicular to the central axis 214 of the rotor510. In certain aspects, when the inlet port 204 is oriented such thatfluid enters the aperture in a direction perpendicular to the centralaxis 214 of the rotor 510, the cam 212 directly or indirectly produceshorizontal displacement of the spring 400, as shown in FIGS. 6A and 6B,for example.

The cam 212 in embodiments of the valve assembly 100 disclosed herein,in any configuration, can have a constant or linear slope, a piecewiselinear slope, a non-linear slope and combinations of such slopes in thesurface(s) that engage the spring 400. If the cam 212 has a linearslope, rotation of the cam 212 increases or decreases the pressuresetting in a linear way. If the cam 212 has a non-linear slope, thepressure, for example, can increase more towards the end of therotation. This allows the possibility of having minute increments ofpressure initially, for example, between 0 and 200 mm H₂O, and largerincrements of pressure thereafter. For example, the cam 212 illustratedin FIGS. 6A and 6B includes a surface with a non-linear slope thatengages the first arm 410 of the spring 400. Specifically, the cam 212includes a projection 218, which alters the rate of increase in thepressure exerted by the cam 212 on the spring 400 as the cam 212rotates. Thus, in certain examples the force exerted by the cam 212 onthe spring 400 increases in a substantially linear manner over themajority of the rotational cycle of the cam 212; however, toward the endof the cycle, the force increases more dramatically due to the influenceof the projection 218.

In certain applications, for example, in the treatment of hydrocephalusin children, it may be desirable to be able to determine whether or notthe patient is still in need of the valve after some time of use orwhether hydrocephalus has become arrested and is no longer in need ofshunting. For example, depending on the cause of hydrocephalus, afterseveral years of using an implanted shunt valve assembly 100, thepatient may no longer need the valve. One method of testing to determinewhether or not the valve is still needed in the patient is tosignificantly increase the pressure of the spring 400 against the valveelement 208, thereby almost completely closing the valve 200, andobserve the patient's condition thereafter. Accordingly, theabove-described configuration in which the step pressure increase issignificantly larger at or close to the maximum pressure position of thespring 400 and cam 212 may advantageously allow this testing to beperformed. If the patient's condition deteriorates after the pressuresetting of the valve 200 is significantly increased, the pressuresetting may simply be decreased again, by rotating the cam 212. Thus,this configuration provides a safe quasi-OFF setting for the valve 200,without having the valve 200 completely closed or removed.

According to certain examples the magnetic motor may include a rotorstop or cam stop 220 that prevents 360 degree rotation of the cam 212,and thereby prevents the valve from being able to transition immediatelyfrom fully open to fully closed, or vice versa, in one step. The cam 212can rotate either clockwise or anticlockwise up to the position set bythe cam stop 220, and then must rotate in the opposite direction. Thus,a full rotation of the cam 212 is required to transition the valve fromfully open to fully closed, or vice versa, rather than only a small stepor incremental rotation.

In certain examples, after the valve assembly 100 is manufactured, acalibration device is typically needed to adjust the pressure settings.For example, in certain embodiments the spring 400 may be constructedsuch that it is linear with respect to each step, that is, with eachstep of rotation of the cam 212, the spring 400 is tensioned so that thepressure of the valve 200 goes up by X amount, and this is true for eachadditional step of rotation. Accordingly, it may be necessary tocalibrate the device to set the cam 212 at a given position andpre-tension the spring 400 to an appropriate pressure for that position.Therefore, after the valve 200 is assembled and during the calibration,there may be a flow of nitrogen (or some other fluid) through the valveassembly.

FIGS. 10A and 10B schematically illustrate an example of the magneticrotor 510 including ten rotor magnet elements 512 arranged in a circle,as discussed above, and configured such that clockwise rotationincreases the pressure setting of the programmable valve 200. FIG. 10Ashows the rotor 510 and the spring 400 in the position of minimumtension on the spring, corresponding to a lowest pressure setting of thevalve 200. FIG. 10B shows the rotor 510 and the spring 400 afterclockwise rotation from position shown in FIG. 10A into the position ofmaximum tension on the spring, corresponding to a highest pressuresetting of the valve 200. As discussed above, the rotor 510 may rotatethrough a plurality of incremental steps, indicated at 518, each stepcorresponding to a defined change in the pressure setting of the valve200. As also discussed above, the rotor 510 may include the cam stop 220which may prevent 360 degree rotation of the cam 212, and therebyprevents the valve from being able to transition immediately from fullyopen to fully closed, or vice versa, in one step. In one example,schematically illustrated in FIGS. 10A and 10B, at the maximum andminimum pressure settings of the valve 200, the cam stop 220 abuts ahousing stop 222. The cam stop 220 and housing stop 222 are sized andarranged such that the cam stop cannot pass the housing stop, therebypreventing further rotation of the cam in the same direction.Accordingly, when the rotor 510 is in the position of the minimumpressure setting of the valve 200 (FIG. 10A), the rotor must rotateclockwise, thereby gradually increasing the pressure setting of thevalve. Counter-clockwise rotation, which would transition the valve 200from the minimum pressure setting to the maximum pressure setting in onestep is prevented by the cam stop 220 and housing stop 222. Similarly,when the rotor 510 reaches the position corresponding to the maximumpressure setting of the valve 200 (FIG. 10B), further clockwise rotationof the cam is prevented by cam stop 220 and the housing stop 222, suchthat the rotor must rotate counter-clockwise, thereby graduallydecreasing the pressure setting of the valve.

As also shown schematically in FIGS. 10A and 10B, in certain examplesthe valve 200 may include a pair of radiopaque markers, namely a rotormarker 224 and a housing marker 226, that can be seen in an X-ray andindicate the position of the rotor 510, and therefore the pressuresetting of the valve 200. In one example the pair of radiopaque markers224 and 226 are localized in such a way that at the lowest pressuresetting of the valve, the two markers are aligned with the center of thecam, as shown in FIG. 10A. The housing marker 226 is fixed in thehousing of the valve 200 and does not rotate with the rotor 510, whereasthe rotor marker 224 rotates with the cam/rotor.

In some embodiments, the radiopaque markers 224, 226 include tantalum.In some embodiments, the radiopaque markers 224, 226 include tantalumspheres and/or tantalum beads.

As discussed above, because embodiments of the valve assembly 100comprise a magnetically actuated rotor 510, the pressure setting of theimplanted programmable valve 200 can be adjusted by positioning anexternal adjustment device (also referred to herein as a valveprogrammer) in proximity to the implanted valve 200 but external to thebody. The valve programmer includes a magnetic field generator, alongwith various control and input/output (I/O) components to allow a user(e.g., a doctor) to control the valve programmer to set and optionallyread the pressure setting of the implanted programmable valve 200. Incertain embodiments, the magnetic field generator can include anarrangement of electromagnets, as discussed below with reference toFIGS. 11A, 13, 15, 16A-H, 17, and 18A-H. In other embodiments, themagnetic field generator can include one or more permanent magnets, andthe valve programmer can be battery operated, as discussed further belowwith reference to FIGS. 11B, 11C, 19-22, 23A-E, and 24.

FIG. 11A illustrates a valve programmer 600 including a transmitter head610 which may be placed over the patient's head at a location over animplanted magnetically-programmable valve 200. The transmitter head 610includes a magnetic field generator, as discussed further below, thatapplies magnetic pulses to selectively magnetize the stator 528 andthereby cause rotation of the rotor 510. Fluid flows from the ventricle,through a ventricular catheter 120, through the implanted valve, intothe distal catheter connected to the connector 140, which then drainsthe fluid at a remote location of the body (such as the right atrium ofthe heart or to the peritoneal cavity). The valve programmer 600 maysend a magnetic signal through the transmitter head 610 to effectrotation of the rotor 510. A control device 620 may be used to controlthe transmitter head 610 to produce the magnetic pulses, as discussedfurther below, and may be coupled to the transmitter head 610 via acommunications link 630, such as a cable or wireless link, for example.

Referring to FIG. 12, according to certain embodiments, the controldevice 620 can include a variety of components or modules to enable auser to control the adjustment device to alter the pressure setting ofthe implantable valve 200, and to determine the current pressure settingof the valve. The control device 620 can include a user interface 622that allows a user to interact with the control device. The userinterface can include one or more displays or input devices, such asinput keys, touch screens, etc., to allow a user to view and adjust thepressure settings of the valve 200. In certain embodiments the controldevice 620 can further include drive circuitry 624 in communication withthe transmitter head 610. A controller 632 may be used to provideinstruction to the drive circuitry 624 to drive the magnetic fieldgenerator in the transmitter head 610 with a predetermined current,duration, cycle, etc., based on instructions received via the userinterface 622, for example. The controller 632 may further receiveinputs from a setting detector 626, and control the user interface 622to display the valve pressure setting responsive to information receivedfrom the setting detector. The controller 632 may be preprogrammed, forexample, by computer instructions stored on a computer readable mediumor device, such as a hard disk drive, an optical disk readable by anoptical disk reader, a flash memory device, and the like. The controldevice 620 may be operated to allow a user to adjust the valve 200through the programmable controller 632 and to determine a setting ofthe valve 200. In some embodiments, the control device 620 may furtherinclude a communication interface 628, which can be used to connect thecontrol device 620 to another device, such as an application server of anetworked computer for similarly controlling or otherwise operating thevalve 200.

FIG. 11B illustrates another embodiment of an external adjustment device640 that includes a single integrated device, rather than a separatetransmitter head 610 and control device 620 as in the example of FIG.11A. According to one example, the external adjustment device 640includes permanent north and south magnets that generate a magneticfield, which when rotated, selectively magnetizes the stator 528 andthereby causes rotation of the rotor 510.

FIG. 11C illustrates an example of an external valve reading device thatincludes a valve reading device (pressure reader) 660 for detecting thepositional aspect of the rotor 510 in determining the pressure settingof the valve 200. In the illustrated example the pressure reader 660includes a mechanical compass; however, in other examples the mechanismcan be electronic, including a magnetic positional sensor, for example.Embodiments of the pressure reader are discussed in more detail below.In certain examples the pressure reader can be incorporated intoembodiments of the valve programmer 600 of FIG. 11A, and configured todetermine the positional aspect of the rotor 510, or otherwise read thepressure setting of the valve 200, when the magnetic field generator inthe transmitter head 610 is off.

According to certain embodiments, valve pressure adjustments can be madeby applying a pulsed magnetic field to the vicinity of the programmableshunt valve as shown diagrammatically in FIGS. 13, 14, 15, 16A-H, 17,and 18A-H. The transmitter head 610 is placed in proximity to theimplanted valve 200. In one embodiment, the transmitter head 610contains four electromagnets, illustrated schematically in FIG. 13 ascoils 1, 2, 3, and 4, which are separately controlled by the externalcontrol device 620 (for example, via drive circuitry 624 as discussedabove). In the example shown in FIGS. 13 and 14 and as discussed above,the magnetically operable motor of the implanted valve 200 includes therotor 510, having twelve rotor magnet elements 512 arranged withalternating polarity in channel 522 of the rotor casing 514), asdiscussed above. The motor further includes the stator 528 positionedbelow the rotor 510. In the illustrated example, the stator 528 has an Xshape. Thus, in this example, the four electromagnets (also referred toas coils) in the transmitter head 610 are positioned such that coils 1and 3 and coils 2 and 4 are closer to one another than are coils 1 and 4and coils 2 and 3, as shown in FIG. 13. The four electromagnets canfurther be positioned equidistant from a central axis 530. When thetransmitter head 610 is positioned properly over the implanted valve200, the central axis 530 of the electromagnets is coincident with theaxis of rotation 214 of the rotor 510, and each electromagnet is alignedat the same angular position as one arm of the stator 528, as shown inFIG. 13. It is not, however, necessary that this alignment be exact.Embodiments are tolerant of alignment errors, which may be unavoidableowing to the inability of the user to see the rotor 510 or the stator528 and to the small size of those elements relative to the size of theexternal electromagnets.

Each of electromagnets 1, 2, 3, and 4 can be energized to have eitherthe north or south polarity facing the stator 528, or each can remainoff altogether. Movement of rotor 510, in the desired direction andthrough the desired angle, is achieved by energizing the electromagnetsin the sequences shown in the tables in FIG. 15 (clockwise rotation) orFIG. 17 (counter-clockwise rotation), which in turn magnetizes thestator 528, which then attracts or repels the rotor magnet elements 512(depending on polarity), causing rotation of the rotor 510.

For example, referring to FIGS. 15 and 16A-H, clockwise motion isachieved by first energizing both electromagnets 1 and 2 to southpolarity, and leaving electromagnets 3 and 4 off (step 1). In the nextstep (step 2) electromagnets 1 and 2 are left off, and electromagnets 3and 4 are both energized to south polarity. In step 3, electromagnets 1and 2 are both energized to north polarity, while electromagnets 3 and 4remain off, and in step 4, electromagnets 1 and 2 are left off whileelectromagnets 3 and 4 are energized to north polarity. The sequencerepeats itself after the fourth step.

The rotor 510 is shown in FIG. 16B in the position reached after thefirst step (the polarities of the rotor magnet elements 512 are thosecorresponding to the bottom surface). As shown in FIGS. 16A and 16B,energizing the electromagnets 1 and 2 such that the south poles aretowards the stator 528, and face towards each other, causes the stator528 to become magnetized with a north polarity. Accordingly, the nownorth-magnetized stator 528 pulls those rotor magnet elements 512 havingsouth polarity towards itself, while repelling those rotor magnetelements 512 having north polarity. The result is clockwise rotation ofthe rotor 510, as indicated by arrow 532. Rotation of the rotor 510 mayfurther be seen through FIGS. 16A-H by observing the changing positionof reference marker 526. Similarly, in step 2 when electromagnets 3 and4 are energized such that the south poles are towards the stator 528,and face towards each other, the stator 528 is again magnetized with anorth polarity, and acts on the rotor magnet elements 512 to inducefurther clockwise rotation of the rotor 510, as shown in FIGS. 16C and16D. FIGS. 16E-H demonstrate the operation corresponding to steps 3 and4 of FIG. 15. In particular, energizing the electromagnets 1 and 2 suchthat the north poles are towards the stator 528, and face towards eachother (step 3), causes the stator 528 to become magnetized with a southpolarity, as shown in FIG. 16E. Accordingly, the now south-magnetizedstator 528 pulls those rotor magnet elements 512 having north polaritytowards itself, while repelling those rotor magnet elements 512 havingsouth polarity. The result is further clockwise rotation of the rotor510, as indicated by arrow 532 and shown in FIG. 16F. Similarly, in step4 when electromagnets 3 and 4 are energized such that the north polesare towards the stator 528, and face towards each other, the stator 528is again magnetized with a south polarity, and acts on the rotor magnetelements 512 to induce further clockwise rotation of the rotor 510, asshown in FIGS. 16G and 16H.

Movement of rotor 510 is influenced predominantly by the stator 528positioned beneath the rotor 510 and close to the rotor magnet elements512 of the rotor 510. Thus, the applied external magnetic field from theelectromagnets 1, 2, 3, and 4 does not directly cause movement of therotor 510, but instead controls magnetization and polarity of the stator528, which then acts upon the rotor magnet elements 512 to inducerotation of the rotor 510. The number of rotor magnet elements 512 andthe shape of the stator 528 are selected such that two conditions aremet. First, when one pair of radially opposite stator arms is alignedwith one pair of radially opposite rotor magnet elements 512 (e.g.,referring to FIG. 16C, stator arms 534 a and 534 b are aligned withrotor magnet elements 512 a and 512 b, respectively) the other twostator arms are each staggered halfway between two of the rotor magnetelements 512, as shown in FIG. 16C, for example. Second, each pair ofradially opposite rotor magnet elements (e.g., 512 a and 512 b in FIG.16C) has the same magnetic polarity. In operation, control device 620energizes the electromagnets closest to the pair of stator armsstaggered between two rotor magnet elements 512, thereby causing therotor 510 to move through an angle corresponding to one half the widthof one rotor magnet element 512. As discussed above, in one examplethere are twelve magnetic rotor elements 512 and thus 24 angularincrements in one full revolution of the rotor 510. Furthermore, thisconfiguration, in which radially opposite rotor magnet elements 512 havethe same magnetic polarity and radially opposite electromagnets are alsoenergized to have the same magnetic polarity facing the stator 528(e.g., south in FIG. 16A) advantageously results in the magneticallyprogrammable valve being highly resistant to other (non-programming)magnetic fields. Randomly applied magnetic fields resulting from naturalphenomena or external devices unrelated to the control device 620 (e.g.,MRI machines) are highly unlikely to have two same poles (e.g., bothpoles being either north or south) applied at opposite ends of thestator 528. To the contrary, an external, non-programming field is farmore likely to have side-by-side north and south poles, which will failto uniformly magnetize the stator 528, as is required for controlledoperation (as shown in FIGS. 16A-H) and therefore will fail to causeunwanted or accidental rotation of the rotor 510. In contrast, aconventional magnetic rotor, such as that disclosed in U.S. Pat. No.4,615,691, for example, the rotor includes radially opposite permanentmagnets having opposite magnetic polarities (as shown in FIG. 9 of U.S.Pat. No. 4,615,691), along with a cross-shaped stator that is magnetizedwith one half having one polarity and the other half having the oppositepolarity, unlike the stator 528 disclosed herein, which is uniformlymagnetized with a single magnetic polarity responsive to the externalprogramming field, as discussed above. Consequently, the conventionaldevice is far more susceptible to unwanted rotation, and thereforeunwanted adjustment of the pressure settings of the valve, due toexternal non-programming magnetic fields.

As discussed above, in one example the rotor 510 includes twelve rotormagnetic elements 512; however, in other examples the rotor 510 can besized and designed to include a different number of rotor magnetelements 512 (e.g., eight), provided that radially opposite elementshave the same magnetic polarity. Further, in other examples in which therotor 510 is configured to be operated by a differently configured valveprogrammer, as discussed in more detail below, the rotor may be sizedand designed to accommodate a number of rotor magnet elements 512 such(e.g., ten) that radially opposite rotor magnet elements have oppositepolarity.

Similar operation can be initiated to induce counter-clockwise rotationof the rotor 510. For example, FIG. 17 is a table, similar to thatillustrated in FIG. 15, showing an example of an energizing sequence ofthe electromagnets of the device of FIG. 13 to effect counter-clockwiserotation of the rotor 510. FIGS. 18A-H illustrate the magneticpolarities of the electromagnets and stator 528, and resulting movementof the rotor 510, corresponding to the sequence shown in FIG. 17.

Thus, referring to FIGS. 17 and 18A-H, counter-clockwise motion isachieved by first energizing both electromagnets 1 and 2 to northpolarity, and leaving electromagnets 3 and 4 off (step 1). In the nextstep (step 2) electromagnets 1 and 2 are left off, and electromagnets 3and 4 are both energized to south polarity. FIGS. 18A-D correspond tosteps 1 and 2, with FIG. 18B showing the rotor 510 in the positionreached after step 1, and FIG. 18D showing the rotor 510 in the positionreached after step 2. As shown in FIGS. 18A-B, energizing theelectromagnets 1 and 2 to north polarity causes the stator 528 to becomemagnetized to south polarity, and induces counter-clockwise rotation ofthe rotor 510, indicated by arrow 536, by acting on the rotor magnetelements 512 as discussed above. Similarly, as shown in FIGS. 18C-D,energizing the electromagnets 3 and 4 to south polarity causes thestator 528 to become magnetized to north polarity, and induces furthercounter-clockwise rotation of the rotor 510, indicated by arrow 536. Instep 3, electromagnets 1 and 2 are both energized to south polarity,while electromagnets 3 and 4 remain off, and in step 4, electromagnets 1and 2 are left off while electromagnets 3 and 4 are energized to northpolarity. FIGS. 18E-H demonstrate the operation corresponding to steps 3and 4 of FIG. 17. In particular, energizing the electromagnets 1 and 2such that the south poles are towards the stator 528, and face towardseach other (step 3), causes the stator 528 to become magnetized with anorth polarity, as shown in FIG. 18E. Accordingly, the nowsouth-magnetized stator 528 pulls those rotor magnet elements 512 havingnorth polarity towards itself, while repelling those rotor magnetelements 512 having south polarity. The result is furthercounter-clockwise rotation of the rotor 510, as indicated by arrow 536and shown in FIG. 18F. Similarly, in step 4 when electromagnets 2 and 3are energized such that the north poles are towards the stator 528, andface towards each other, the stator 528 is magnetized with a southpolarity, and acts on the rotor magnet elements 512 to induce furthercounter-clockwise rotation of the rotor 510, as shown in FIGS. 18G and18H. The sequence repeats itself after the fourth step. Each stepresults in an increment of angular movement of the rotor 510corresponding to one half the width of one rotor magnet element 512, asdiscussed above.

Although operation of the magnetic motor and transmitter head 610 isdiscussed above with reference to a rotor including twelve rotor magnetelements 512, given the benefit of this disclosure, those skilled in theart will appreciate that operation of the transmitter head 610 and itselectromagnets can be adjusted for a rotor having a different number ofrotor magnet elements, such as ten rotor magnet elements, for example.

Thus, using an implanted valve 200 having the magnetic motor discussedabove, along with an external controller that includes a control device620 and transmitter head 610 having the four electromagnets 1, 2, 3, and4, the pressure setting of the implantable valve can be non-invasivelycontrolled in small increments. The configuration of the cam 212 and thetension in the spring 400 can be designed and calibrated such that eachangular increment of the rotor 510 produces a well-defined selectedchange in the pressure setting of the valve (e.g., 10 mm H₂O). In oneexample, the control device 620 can be configured to allow the user toenter a desired pressure setting for the valve, and then automaticallyactivate the transmitter head 610, using one of the sequences shown inFIG. 15 or 17, for example, to achieve the selected pressure setting.

In one example, to ensure an accurate pressure setting of the valve 200,the control device 620 can be configured to first activate thecounter-clockwise rotation sequence of FIG. 17 to set the valve 200 toits fully open position, and then activate the clockwise rotationsequence of FIG. 15 to set the valve 200 to the selected pressuresetting entered by the user. According to certain examples, when thecounter-clockwise rotation sequence is activated, the valve programmeris configured to actuate the rotor 510 to rotate through a sufficientnumber of counter-clockwise steps such that the rotor will be positionedsuch that the valve 200 has its lowest pressure setting. As discussedabove, the presence of the cam stop 220 and housing stop 222 prevent therotor from continuing to rotate past the minimum pressure settingposition. After the programmer stops the counter-clockwise rotationsequence, it may start the clockwise sequence from a known position (theposition corresponding to the minimum pressure setting and with the camstop 220 abutting the housing stop 222). The valve programmer 700 mayactuate the rotor 510 to rotate through a selected number of clockwisesteps so as to program the valve 200 to the pressure setting selected bythe user.

Although the example discussed above uses clockwise rotation of therotor 510 to program the pressure setting of the valve 200 (andcounter-clockwise rotation to set the rotor to a known position fromwhich to begin the programming sequence), those skilled in the art willappreciate, given the benefit of this disclosure, that the system (valveand programmer) can instead be configured for the opposite arrangement,namely to use counter-clockwise rotation of the rotor to program thepressure setting of the valve (and clockwise rotation to set the rotorto a known position from which to begin the programming sequence).

In some instances it may be preferable that the external valveprogrammer can be battery operated. Transmitter heads such astransmitter head 610 that include electromagnets may require too muchpower (to energize the electromagnets) to be battery-powered.Accordingly, further aspects and embodiments are directed to a valveprogrammer, such as the example valve programmers illustrated in FIG.11B, that incorporates permanent magnets along with a small DC motor,such as a stepper motor, for example, to provide a very low powercontroller that can be used with the implanted valve 200 and that can bebattery-powered.

Referring to FIG. 19 there is illustrated a block diagram of one exampleof a valve programmer 700 incorporating permanent magnets rather thanelectromagnets. The valve programmer 700 includes a controller 702, auser interface 704, a battery 706, a stepper motor 708, and a permanentmagnet assembly 710. These components can be packed together in a singlehousing that can be held near the implanted valve 200 to control andadjust the pressure setting of the valve 200, as illustrated in FIG.11B, for example. Alternatively, certain components, such as thepermanent magnet assembly 710, stepper motor 708 and battery 706 can bepackaged together, optionally including a controller that may performall or some of the functionality of the controller 702, and userinterface 704 (optionally with a controller that may perform all or someof the functionality of the controller 702) can be packaged separatelyto allow the user to more conveniently view the user interface 704 whileoperating the valve programmer 700. For example, the user interface 704can be implemented as an application running on a mobile computingdevice, such as a smart-phone or table computer, for example, thatallows the user to view the pressure setting of the valve 200 and entercommands (such as to select a desired pressure setting of the valve200). The user interface 704 can receive pressure setting informationfrom the controller 702, for example, and transmit the user commands tothe other, optionally separately packaged components of the valveprogrammer 700, for example to the controller 702 or to the steppermotor 708 to actuate the permanent magnet assembly 710 to adjust thepressure setting of the valve 200.

FIG. 20A is an illustration of one example of a permanent magnetassembly 710 a that can be used in the valve programmer 700 according tocertain embodiments. The permanent magnet assembly 710 a includes ahousing 712 and a rotatable magnet guide 714 disposed within the housing712 and configured to rotate about a central axis of rotation 716. Inone example, the stepper motor 708 drives rotation of the magnet guide714 under control of the controller 702. The rotation of the magnetguide 714 can be continuous or a series of discrete steps. A pluralityof permanent magnets are mounted to or within the magnet guide 714 suchthat the permanent magnets rotate with the magnet guide 714. In theexample illustrated in FIG. 20A there are four permanent magnets 722,724, 726, and 728. The two radially opposite permanent magnets have thesame magnetic polarity. For example, as illustrated in FIG. 20A,permanent magnets 722 and 724 have north polarity while permanentmagnets 726 and 728 have south polarity. This configuration isappropriate for controlling the rotor 510 having twelve rotor magnetelements 512, for example.

Those skilled in the art will appreciate that a wide variety ofmodifications to the permanent magnet assembly 710 can be made. Forexample, although the four permanent magnets 722, 724, 726, and 728 areillustrated in FIG. 20A as being round, they may have other shape, suchas, but not limited to, rectangular, oval, bar-shaped, rod-shaped, andthe like. Additionally, there may be more than or fewer than fourpermanent magnets. For example, FIG. 20B illustrates a configuration inwhich the permanent magnet assembly 710 b includes a pair of permanentmagnets 732 and 734 of opposite magnetic polarity. This configurationmay be appropriate for controlling the rotor 510 having ten rotor magnetelements 512, instead of twelve, for example. In another example, thepermanent magnet assembly 710 b can include a single diametricallymagnetized permanent magnet, rather than two separate magnets ofopposite polarity. It is further to be appreciated that any of thepermanent magnets 722, 724, 726, 728, 732, or 734 can be comprised of acluster of multiple permanent magnets of the same magnetic polarity,rather than being single permanent magnets. Actuated by the steppermotor 708, the magnet guide 714, and therefore the plurality ofpermanent magnets 722, 724, 726, and 728, or 732 and 734, rotate aboutthe axis of rotation 716. When the valve programmer 700 is placed overthe implanted valve 200, the permanent magnet assembly 710 magnetizesthe stator 528. Rotation of the magnet guide 714 changes themagnetization of the stator 528, and thereby induces movement of therotor 510, similarly as discussed above with respect to the transmitterhead 610.

FIGS. 21A-E diagrammatically illustrate an example of the changingmagnetic polarity of the stator 528, and resulting rotation of the rotor510, responsive to rotation of the magnet guide 714 for the example ofthe valve programmer 700 including the permanent magnet assembly 710 aof FIG. 20A. In FIGS. 21A-E, the permanent magnet assembly 710 a isdiagrammatically represented by ring 718. As shown in FIG. 21A, forexample, the ring 718 has four magnetic quadrants, two of each magneticpolarity (730 a and 730 c are north, and 730 b and 730 d are south) andwith radially opposite quadrants having the same magnetic polarity,corresponding to the four permanent magnets 722, 724, 726, and 728 shownin FIG. 20A. The ring 718 includes a controller reference marker 736which is intended to illustrate rotation of the magnet guide 714 throughFIGS. 21A-E and which does not necessarily correspond to a physicalstructure. Similarly, a rotor reference marker 538 is illustrated on oneof the rotor magnet elements 512 to illustrate rotation of the rotor 510through FIGS. 21A-E.

Referring to FIG. 21A, in a first position, the two oppositelypositioned permanent magnets having south polarity (permanent magnets726 and 728 in FIG. 20A) corresponding to quadrants 730 b and 730 d ofring 718 cause the opposing stator arms 534 c and 534 d to which theyare closest or aligned to be magnetized to north. Similarly, the othertwo oppositely positioned permanent magnets having north polarity(permanent magnets 722 and 724 in FIG. 20A) corresponding to quadrants730 a and 730 c of ring 718 cause the other two opposing stator arms 534a and 534 b to which they are closest or aligned to be magnetized tosouth. The stator arms 534 a and 534 b now magnetized to south arestaggered between two rotor magnet elements of opposite magneticpolarity, and therefore pull the north-polarized rotor magnet elements512 a and 512 b while repelling the south-polarized rotor magnetelements 512 c and 512 d, resulting in rotation of the rotor 510 to theposition shown in FIG. 21B. The rotor 510 rotates through an anglecorresponding to one half the width of one rotor magnet element 512, asillustrated by the relative displacement of the rotor reference marker538 from FIG. 21A to FIG. 21B. The degree of rotation of the rotor 510corresponds to a 45 degree rotation of the ring 718, as illustrated bythe relative displacement of the controller reference marker 736 fromFIG. 21A to FIG. 21B.

In FIG. 21A, the four permanent magnets 722, 724, 726, and 728,represented by quadrants 730 a-d of the ring 718, are each aligned withone of the stator arms 534 a-d, respectively. Referring to FIG. 21B, inthis second position, which is achieved by 45 degrees of rotation of thering 718 (i.e., as indicated by the reference marker 736 of thepermanent magnet assembly 710 a) from the first position (FIG. 21A),each of the four permanent magnets 722, 724, 726, and 728, representedby quadrants 730 a-d of the ring 718, is now staggered across two statorarms. As a result, each of the stator arms 534 a-d has a split magneticpolarization, with a portion of each arm being magnetized to north andanother portion being magnetized to south, as shown in FIG. 21B.

Referring to FIG. 21C, a further 45 degree rotation of the magnet guide714 as indicated by the reference marker 736 re-aligns the fourpermanent magnets 722, 724, 726, and 728 of the permanent magnetassembly 710 a with the stator arms 534 a-d. As shown, opposing statorarms 534 a and 534 b are now magnetized to north, and opposing statorarms 534 c and 534 d are now magnetized to south. The stator arms 534 aand 534 b now magnetized to north are again staggered between two rotormagnet elements 512 of opposite magnetic polarity, and therefore repelthe north-polarized rotor magnet elements 512 a and 512 b and pull thesouth-polarized rotor magnet elements 512 c and 512 d, resulting inanother angular increment (corresponding to one half the width of onerotor magnet element 512) of rotation of the rotor 510 to the positionshown in FIG. 21D.

Referring to FIG. 21D, a further 45 degree rotation of the magnet guide714, represented by ring 718 and indicated by the reference marker 736,again results in the arms of the stator 528 each having split magneticpolarity. Another 45 degree rotation of the magnet guide 714 returns thestator 528 to the magnetic polarity configuration of FIG. 21A and causesrotor 510 to rotate by another angular increment, as shown in FIG. 22.The cycle continues to repeat with further rotation as shown in FIG. 21Eof the magnet guide 714 for the external permanent magnets 722, 724,726,and 728 of FIG. 20A.

Thus, for the implementation of the rotor 510 shown in FIG. 4C, forexample (circular arrangement of twelve rotor magnets 512) and the valvecontroller including the permanent magnet arrangement shown in FIG. 20A,180 degrees of rotation of the magnet guide 714 (as can be seen bycomparing the positions of the controller reference marker 736 in FIGS.21A and 21E) results in four angular increments of rotation of the rotor510 (corresponding to movement equivalent to two times the width of onerotor magnet element 512), as may be seen by comparing the positions ofthe rotor reference marker 538 in FIGS. 21A and 21E. Thus, threecomplete revolutions of the magnet guide 714 results in one completerevolution of the rotor 510. This “gear reduction” effect achievedthrough the indirect action of the valve programmer 700 on the rotor 510(via the stator 528) advantageously allows for very small incrementalmovements of the rotor 510 without requiring correspondingly smallmovements in the valve programmer 700. This can improve ease of use ofthe valve programmer 700 by a user, or simplification of manufacture ofthe valve programmer 700 because the magnet guide 714 is not required tobe as small as the rotor 510 of the implantable valve 200.

Adjustments in the gear ratio between the valve programmer 700 and therotor 510 can be achieved by altering the configuration (e.g., number ofmagnets) of the permanent magnet assembly or the rotor 510. For example,using a similar rotor arrangement as shown in FIG. 4C, but with tenrotor magnets instead of twelve rotor magnets, and the permanent magnetassembly with two permanent magnets 732 and 734 of FIG. 20B instead ofthat of FIG. 20A, results in five complete revolutions of the magnetguide 714 causing one complete revolution of the rotor 510. As will beappreciated by those skilled in the art, given the benefit of thisdisclosure, various other combinations of external permanent magnets androtor magnets can be implemented, and are considered as part of thisdisclosure and intended to be within the scope of the present invention.

FIG. 22 is a flow diagram showing rotation of the valve programmer andcorresponding changing magnetization of the stator and rotation of therotor, in accord with the operation discussed above with reference toFIGS. 21A-E. Arrows 119A show rotation of the rotor at each step in theflow diagram.

In certain examples the valve programmer 700 can be packaged in ahand-held housing 762 such that it is comfortable and easy for a user touse. FIGS. 23A-23D illustrate an example 760 of the valve programmer700. In this example, the valve programmer 760 has a shape that issimilar to a computer mouse. As shown, in some embodiments, the valveprogrammer 760 has rounded corners on its outer surfaces, and may havean overall rounded shape, which may be easy and/or comfortable for auser to hold. In some embodiments, the valve programmer 760 can beeasily held by a user in one hand.

FIG. 23A shows a top view of the valve programmer 760. FIG. 23B shows anunderside view of the valve programmer 760. FIG. 23C shows an end viewof the valve programmer 760, and FIG. 23D shows a perspective view ofthe valve programmer 760.

As discussed above, the valve programmer 760 can be battery operated.Accordingly, in some embodiments, the housing 762 can house one or morebatteries, along with the magnet assembly 710 (not shown in FIGS.23A-D). As discussed above, in some embodiments, the valve 200 includesa ten magnet stepper motor, and the magnet assembly 710 of the valveprogrammer 760 two oppositely magnetized magnets for rotating thestepper motor of the valve 200. The two oppositely magnetized magnetshave opposite fields oriented downwardly within the valve programmer760. In some embodiments, the programmer magnets have a surface fieldstrength of 6000 gauss.

As shown in FIGS. 23A and 23D, the valve programmer 760 may include auser interface 764 that shows information such as the pressure setting,the battery status 770, and optionally other information. For example,the center of the user interface 764 screen may show the pressure thatwas selected (in a digital read-out). The border of the screen mayinclude an indication of what an X-ray would show, or the position ofthe valve rotor that may be indicated by a pressure reader, as discussedfurther below.

The valve programmer 760 includes an interface mechanism to allow a userto select the pressure setpoint of the valve programmer 760, and therebyto set the pressure of the valve 200. In some embodiments, as shown inFIG. 23A, the valve programmer 760 includes a first button 761 a toincrease the pressure setpoint and a second button 761 b to decrease thepressure setpoint. Alternatively, the valve programmer 760 may include awheel (such as the wheel shown in the embodiment of FIG. 23E) that isrotatable in a first direction to increase the pressure setpoint, androtatable in a second direction to decrease the pressure setpoint. Insome embodiments, the valve programmer 760 can include the first button761 a, the second button 761 b, and the wheel. In some embodiments, thevalve programmer 760 can set the valve 200 to one of 20 pressuresettings, as discussed above. In some embodiments, the highest pressuresetting does not completely close the valve 200. This can be useful fortesting whether the patient still needs the valve 200 without completelyclosing the valve 200 and thereby avoiding potential injury to thepatient.

The valve programmer 760 may further include a programming button 769that when pressed causes the valve programmer 760 to actuate the magnetassembly 710 to program the valve 200. In some examples the programmingbutton 769 can be located on the front edge of the housing 762, as shownin FIG. 23A.

The valve programmer 760 may also include an on/off button 772, as shownin FIGS. 23A and 23C.

Referring to FIGS. 23B and 23C, the housing 762 of the valve programmer760 can be shaped to facilitate correctly orienting the valve programmer760 over an implanted valve 200 to program the pressure setting of thevalve 200. In certain examples, the housing 762 includes a molded cavity763 defined by sidewalls 765 on the bottom of the valve programmer 760.The cavity 763 is shaped and sized to correspond at least approximatelyto the shape and size of the implanted valve 200. The cavity 763includes a pair of channels 767 defined in the sidewalls 765. Asdiscussed above, the inlet port of the programmable valve 200 can beconnected to an inflow catheter, and the outlet port of the programmablevalve 200 can be connected to a drainage catheter. The channels 767 canbe sized and arranged such that, when the valve programmer 760 is placedover the implanted valve 200 on the patient's head, the channels 767align with the inflow catheter and the drainage catheter, therebyassisting to correctly align the valve programmer 760 with the implantedvalve 200.

After the user sets the desired pressure setpoint on the programmer 760,the user places the programmer 760 on top of the valve 200. Next, theuser presses the programming button 769 on the front edge of theprogrammer 760 to start the programming.

FIG. 23E shows a top view of a valve programmer 777. The valveprogrammer 777 has a housing 762 that can be held in a user's hand. Thevalve programmer 777 includes a user interface 764 that showsinformation such as the pressure setting, the battery status 770, andoptionally other information. The valve programmer 777 includes a wheel787 that is rotatable in a first direction to increase the pressuresetpoint, and rotatable in a second direction to decrease the pressuresetpoint. In FIG. 23E, the wheel partially extends horizontally beyond aside of the housing 762 so that it can be rotated by a user's finger.

FIG. 24 is a flow diagram illustrating an example of a method 1100 ofoperating a valve programmer 700, such as the valve programmer 760 ofFIGS. 23A-D or the valve programmer 777 of FIG. 23E. In step 1102, theuser turns on the valve programmer 760 by pressing the on/off button 772on the programmer. In some embodiments, the valve programmer 760 turnson when the user presses and holds the on/off button 772 for twoseconds. After being turned on, the valve programmer 760 proceeds to theinitial mode at step 1104. In the initial mode, the valve programmer 760performs a self-test in which the motor turns counterclockwise andcounts the steps for one turn, and compares the number of steps to thenumber of steps that should be needed for one turn. In some embodiments,the motor self-test is always active when the motor is turning. In someembodiments, the valve programmer display (user interface screen) 764shows all icons for three seconds in step 1104. If the charge on thevalve programmer battery is too low, the valve programmer 760 proceedsto step 1106, in which a battery status indicator 770 or indicatorflashes on the user interface screen 764 and the valve programmer 760turns off. In some examples, if the battery charge of the valveprogrammer 760 is low, the battery status indicator 770 flashes slowlyon the programmer display 764, and if the battery charge is extremelylow, the battery status indicator 770 flashes quickly on the programmerdisplay 764.

If the battery charge is sufficient, the valve programmer 760 proceedsto step 1108, which is edit mode. The battery status may be displayed onthe user interface screen 764, as discussed above. In the edit mode ofstep 1108, an icon showing that the edit mode is enabled appears on theprogrammer display 764. In the edit mode, a user can press the increasebutton 761 a or the decrease button 761 b to increase or decrease thevalve programmer's pressure setpoint for the implanted valve 200. Inother examples in which the valve programmer 760 includes a wheel 787for pressure setpoint adjustment rather than the buttons 761 a, 761 b,the user can rotate the wheel in step 1108 to select a desired pressuresetting.

Once the pressure setpoint has been selected, the valve programmer 760is ready to be used to program an implanted valve 200. Accordingly, theuser can place the valve programmer 760 on a patient's head over theimplanted valve 200, using the shape of the housing 762 to correctlyalign the valve programmer 760 with the implanted valve 200, asdiscussed above. To begin programming the valve 200, the user pressesthe programming button 769 on the valve programmer 760, and theprogramming mode at step 1110 is entered.

In the programming mode, the programmer display 764 may show theselected pressure setpoint value along with a lock symbol, as shown inFIG. 23A, for example.

In one example, to ensure an accurate pressure setting of the valve 200,the valve programmer 700 can be configured to first actuate rotation ofthe magnet guide 714 in one direction (e.g., counter-clockwise) to setthe valve 200 to its fully closed position, and then begin a sequence ofrotations in the opposite direction (e.g., clockwise) to set the valve200 to the selected pressure setting entered by the user. Accordingly,in certain embodiments after predetermined time period, for example, onesecond, the valve programmer 760 proceeds to step 1112, in which theprogrammer magnets turn counterclockwise to initialize the valve 200.For example, the programmer magnets of a permanent magnet assembly 710a, 710 b can first be rotated counterclockwise for approximately sixturns so that the cam of the programmable valve 200 is at its lowestposition. After the initial position is reached, the valve programmer760 proceeds to step 1114, in which the programmer magnets start to turnclockwise. While the programmer magnets are turning the valve programmer760 displays the current and final positions for the valve 200. When thefinal position of the programmer magnets is reached, the valveprogrammer 760 proceeds to step 1116, in which an alert, such as anaudible alert, indicates that the selected pressure setpoint has beenreached. After a predetermined time period, for example, three seconds,the valve programmer 760 returns to the edit mode of step 1108. At thisstage, a user can turn the valve programmer 760 off by pressing anon/off button 772. In some embodiments, after a certain time period,e.g., 60 seconds, of no user interaction with the valve programmer 760,the valve programmer 760 turns off automatically.

Returning to FIGS. 14, 16A-H, 18A-H, 21A-E, and 22, in theabove-discussed examples, the stator 528 has an X shape, as shown inFIG. 14, for example, and is a “solid” or unitary structure. The shapeof the stator 528 may vary between a + shape, with a 90° angle betweenthe stator arms to a very narrow X shape, for example. In addition,according to certain embodiments, the stator 528 can be implementedusing a plurality of discrete stator elements, rather than a singlesolid or unitary structure. FIGS. 25A-C illustrate three schematicexamples of stators with different shapes, in combination with atwelve-magnet rotor. FIG. 25A shows an example of a +-shaped unitarystator 540. FIG. 25B shows an example of a stator including four statorelements 542 placed beneath the rotor magnet elements 512 at positionsroughly corresponding to the tips of the four stator arms in the exampleshown in FIG. 25A. In the example illustrated in FIG. 25B, the fourstator elements 542 are configured as four circular dots; however, thestator elements may have any of variety of other shapes. For example,FIG. 25C illustrates another example of the stator including four statorelements 544 configured as “double circular dots” or extended ovals. Inother examples, the stator elements 542 or 544 may be squares orrectangles, or have other geometric or non-geometric shapes.

In each of the examples shown in FIGS. 25A-C, the angle 546 between thestator “arms” is approximately 90°; however, as discussed above, theangle 546 may vary. As will be appreciated by those skilled in the art,given the benefit of this disclosure, the angle 546 may have any valuebetween 90° and a non-zero smallest value (an angular value of zero orvery close to zero results in a two-arm stator, instead of a four-armstator, which would change the operation of the magnetic motor) that maybe dependent on the size of the stator 528 and the configuration of therotor 510, for example. FIGS. 26A-C illustrate further examples ofstators in which the angle 546 is approximately 75°. In particular, FIG.26A shows an example of an X-shaped unitary stator 540 a in which theangle between the closer two stator arms is 75° and therefore thecomplimentary angle between the further apart stator arms is 105°. FIGS.26B and 26C show examples stators including four discrete statorelements 542 and 544, respectively, in which the angle 546 is 75°. Incertain examples, the value of the angle 546 may be selected based atleast in part on achieving resistance to external non-programmingmagnetic fields (e.g., from an MRI or other magnetic field generator notassociated with the valve programmer) and desired movement of the rotor510 (e.g., specific incremental movements of the rotor that correspondto particular incremental pressure settings of the valve). In certainexamples, it may be desirable to configure the stator 528 such that themotor has a relatively high cogging torque. Cogging torque correspondsto the force required to keep the rotor 510 in a particular position. Ahigh cogging torque may increase the motor's resistance or immunity toexternal non-programming magnetic fields, and can also prevent the rotor510 from being moved by the counterforce of the spring 400.

The use of discrete stator elements 542 or 544, rather than a solidstator, reduces the amount of magnetic material as compared to theexamples of the stator 540, 540 a as exemplified in FIGS. 25A and 26A.The magnetization of the stator elements 542 or 544 from an externalmagnetic field acts to rotate the rotor 510 in a similar manner asdescribed above with reference to FIGS. 16A-H, 18A-H, 21A-E, and 22. Therotation of the rotor 510 may be accomplished with either externalelectro-magnets, such as discussed above and shown in FIG. 13, forexample, or with external permanent magnets, such as discussed above andshown in FIGS. 20A and 20B, for example. In certain examples, the statorelements 542 may each be slightly larger (e.g., larger diameter ifcircular) than the rotor magnet elements 512. For example, if the rotormagnet elements 512 have a diameter of 1.3 mm, the circular statorelements 542 shown in FIG. 25B or 26B may have a diameter of 1.4 mm.

As discussed above, according to certain embodiments the programmablevalve 200 can include a magnetic indicator mechanism by which to allow adoctor, for example, to determine a pressure setting of the valve 200using an external magnetic sensor, such as a Hall sensor for example,without requiring X-rays or other imaging techniques. In particular, incertain examples the magnetic motor can include one or more reference orindicator magnets that indicate a position of the rotor 510. Asdiscussed above, the rotor position is directly correlated to thepressure setting of the programmable valve 200. Accordingly, in someexamples the external valve programmer 700 can include a magnetic sensorconfigured to read or detect the pressure setting of the implanted valve200 based on the indicator magnet(s). In other examples, a separatepressure reader can be provided, as discussed further below.

According to certain embodiments, the indicator mechanism can beincorporated into the rotor 510. For example, as discussed above, therotor 510 can include reference or positioning magnet elements 524positioned on top of certain ones of the rotor magnet elements 512, asillustrated in FIGS. 4A, 5, 6A, and 14. FIG. 27 illustrates a schematicexample of the rotor 510 including three reference magnet elements 524a, 524 b, and 524 c positioned above certain ones of the rotor magnetelements 512. In the illustrated example, reference magnet element 524 ahas north magnetic polarity, and reference magnet elements 524 b and 524c are positioned approximately radially across from reference magnetelement 524 a (on either side of the rotor magnet element 512 that isdirectly radially opposite the reference magnet element 524 a) and bothhave south magnetic polarity. As discussed above, the rotor magnetelements 512 are arranged with alternating magnetic polarity and suchthat each two rotor magnet elements 512 that are directly radiallyopposite one another have the same magnetic polarity. Accordingly, inorder to provide a reference magnet that has both a north pole and asouth pole and that spans the rotor 510, an arrangement of threereference magnet elements 524 such as that shown in FIG. 27 can be used.As discussed above, in other embodiments, the rotor 510 may include anumber of rotor magnet elements 512 other than twelve. For example, therotor 510 may include ten magnet elements. In such an example, only tworeference magnet elements 524 may be used because the opposing rotormagnet elements in a ten-magnet rotor have opposite polarities, unlikethe twelve-magnet rotor. In another example in which the rotor 510includes ten magnet elements, four reference magnets (twoopposingly-arranged pairs) can be used. Thus, as will be appreciated bythose skilled in the art, given the benefit of this disclosure, variousnumbers and arrangements of reference magnet elements 524 can be used,at least partially based on the configuration of the rotor 510.Additionally, in certain embodiments, rather than including separatereference magnet elements 524, the rotor magnet elements 512corresponding to the desired positions of the reference magnet elementscan simply be made “taller” than the other rotor magnet elements, andthereby act as both rotor magnet elements that effect rotation of therotor 510 and position-indicating magnets.

In other examples, instead of positioning the reference magnet elements524 above the rotor magnet elements 512, as shown in FIGS. 4A, 5, 6A,14, and 27, the reference or positioning magnet elements can bepositioned to the side(s) of the rotor 510. FIGS. 28A-28C show examplesof motor configurations in which vertically oriented (relative to thehorizontally oriented rotor magnet elements 512) side positioning magnetelements 553 are positioned radially outward of the rotor magnetelements 512. As discussed further below with reference to FIG. 32, thepositioning magnets orient an indicator magnet (not shown in FIGS.28A-C) that can be read by the pressure reader 660, for example, toindicate a position of the rotor 510 and therefore the pressure settingof the valve 200. Referring to FIG. 28A, in there is illustrated anexample in which two side positioning magnet elements 553 are provided.In this example, the polarity of the respective inner face 555 (i.e.,face closer to the rotor magnet elements) of each side positioningmagnet element 553 is opposite to the polarity of the top face of theadjacent rotor magnet element 512. In some embodiments, each sidepositioning magnet 553 has, for example, a 1.0 millimeter diameter and aheight of 0.3 millimeters. FIG. 28B shows another example in which fourside positioning magnet elements 557 are provided. In this example, thepolarity of the respective inner face 555 of each side positioningmagnet element 557 is the same as the polarity of the top face of theadjacent rotor magnet element 512. In some embodiments, each sidepositioning magnet 557 has, for example, a diameter of 0.85 millimetersand a height of 0.25 millimeters. FIG. 28C shows another example inwhich two side positioning magnet elements 559 are provided. In contrastto the example shown in FIG. 28A, in which the two side positioningmagnet elements 553 are placed diametrically opposite one another acrossthe rotor 510, in the example shown in FIG. 28C the two side positioningmagnet elements are positioned in a same hemisphere of the rotor 510.The polarity of the respective inner side 555 of each side positioningmagnet 559 is the same as the polarity of the top face of the adjacentrotor magnet. In some embodiments, each side positioning magnet 559 has,for example, a diameter of 1.0 millimeter and a height of 0.3millimeters.

Referring to FIG. 29 there is illustrated a block diagram of an exampleof an external valve programming assembly 800 that incorporates amagnetic sensor 812 configured to detect a magnetic signal from thereference magnet elements 524 or indicator magnet (positioned by thepositioning magnet elements 553, 557, or 559, for example) and derivetherefrom a position of the rotor 510 and corresponding pressure settingof the valve 200. As shown in FIG. 29, the valve programming assembly800 can include a transmitter head 810 including a magnet assembly 814(such as either the permanent magnet assembly 710 or a collection ofelectromagnets such as described above with reference to transmitterhead 610) for adjusting the pressure setting of the valve 200 andcommunications/control circuitry 816 (such as an electroniccommunications port, motor, actuator, drive circuitry, and the like) asmay be needed to control and operate the magnet assembly 814. The valveprogramming assembly 800 further includes a control device 820 thatincludes a user interface 822 to allow the user to view information,such as the current pressure setting of the valve 200, for example, andprovide control commands, such as a desired pressure setting of thevalve 200, for example, along with communications/control circuitry 824as may be needed to operate the control device 820 or communicate withthe transmitter head 810. In certain examples, the transmitter head 810and control device 820 are separate and communicate via a wired orwireless communication link 804. In other examples, the transmitter head810 and control device 820 can be packaged together, as indicated bydashed line 802, such as in the valve programmer 760. The magneticsensor 812 can be in communication with either thecommunications/control circuitry 816 in the transmitter head 810 or thecontrol device 820. In certain examples in which the magnet assembly 814includes electromagnets that can be turned off, the magnetic sensor 812may be packaged in the transmitter head 810. In other examples, it canbe a packaged as a separate unit.

In one embodiment including the magnetic sensor 812 in the transmitterhead 810 allows the pressure setting of the implanted valve 200 to bedetected and communicated to the control device 820. In one example, themagnetic sensor 812 detects the position of the rotor 510 inside thevalve 200 and translates the detected position into a pressure settingreading. Such correlations between rotational position and pressuresettings can be determined for each valve according to a calibrationprocess. The correlation can provide a look-up capability in which arotational position can be translated into the pressure setting, andvice versa. A resolution of such pressure adjustment can be accomplishedaccording to the techniques employed herein (e.g., based on a known sizeof the rotor magnet elements 512). Alternatively, or in addition, aselection of the spring type and/or spring constant in combination witha shape of the cam can be used to control pressure variations perrotational step. The magnetic sensor 812 can be a Hall sensor orcompass, for example.

According to certain embodiments, a valve programming assembly, such asthe valve programming assembly 800, can include a valve programmer, suchas the valve programmer 760 discussed above, and a separate pressurereader. The pressure reader can be used to read the pressure setting ofan implanted programmable valve 200, and the valve programmer 760 can beused to program the pressure setting of the implanted valve 200, asdiscussed above. The pressure reader can be a compass that includes amagnet configured to provide a pressure reading based on an orientationof the magnet. The compass can be a mechanical compass or an electroniccompass.

In some embodiments, the pressure reader can be hand-held. In someembodiments, the pressure reader is electronic. In certain examples thepressure reader can have a physical appearance that is very similar tothat of the valve programmer 760, for example.

FIGS. 30A and 30B illustrate an example of a pressure reader 660according to certain embodiments. FIG. 30A is a perspective view of thepressure reader 660 and FIG. 30B is a top view. A magnet of the pressurereader 660 is oriented with respect to the valve 200 by placing thepressure reader 660 over an implanted valve 200 such that the arrow 662on the upper surface of the pressure reader 660 is aligned with thedirection of the flow of fluid through the valve 200. The pressurereader 660 can be shaped and sized to facilitate its alignment with animplanted valve 200. For example, the pressure reader 660 can include arecess or cavity on its lower surface that corresponds to the size andshape of the implanted valve 200, similar to as discussed above withrespect to the valve programmer 760. As shown in FIGS. 30A and 30B, thepressure reader 660 can have a circular shape, and may include a displayhaving a range of pressure settings arranged around its circumference.The display can be mechanical or electronic. When the pressure reader660 is placed over and aligned with the implanted valve 200, a pressureindicator 664 points to a pressure setting on the pressure reader 660(as shown in FIG. 30B) that corresponds to a pressure setting of thevalve 200, based on the reference magnet elements as discussed above.

FIG. 31 shows an example of a method 1000 of operating a pressure readersuch as the pressure reader 660 of FIGS. 30A-B. In step 1002, a userturns on the pressure reader 660. In some embodiments, the pressurereader 660 turns on when the user holds down an on/off button on thepressure reader for a predetermined time period, such as two seconds,for example. After being turned on, the pressure reader 660 proceeds toits initial operation mode in step 1004. In the initial mode of step1004, the pressure reader sensor is calibrated to remove or compensatefor the effects of the earth's magnetic field, for example. During thecalibration, devices that may generate magnetic fields, such as thevalve programmer 760, should be kept away from the pressure reader 660.In certain embodiments in which the pressure reader 660 includes anelectronic display, the display can include a battery status indicator,similar to as described above with reference to the valve programmer760. According to certain embodiments, if the battery charge of thepressure reader 660 is too low, the battery status indicator may flash,and then the pressure reader proceeds to step 1006, in which thepressure reader turns itself off. During operation of the pressurereader 660, if the battery charge becomes too low, the battery statusindicator may flash to indicate to the user that the batteries of thepressure reader need to be replaced. If the battery charge becomesextremely low, the battery status indicator may begin to flash morequickly, and eventually the pressure reader 660 may turn itself off.

If the battery charge of the pressure reader 660 is sufficient, thepressure reader 660 performs the magnetic sensor calibration in step1004, and then the pressure reader 660 proceeds to step 1008; searchingmode. During the searching mode, the user may position the pressurereader 660 on a patient's head over an implanted valve 200. In thesearching mode of step 1008, a search icon, such as a magnifying glassicon, may appear on an electronic display of the pressure reader 660 toshow the user that the strength of the detected magnetic field is toolow. This prompts the user to reposition the pressure reader 660 so thatthe detected magnetic field is stronger. If the detected magnetic fieldstrength cannot be improved, this may indicate to the user that thepressure reader 660 magnetic field indication is not reliable.

When the pressure reader 660 detects a magnetic field with sufficientstrength, the display of the pressure reader 660 shows the direction ofthe magnetic field of the valve at step 1010, which corresponds to thepressure setting of the valve. For example, as shown in FIG. 30A, thepressure indicator 664 can indicate the pressure setting of the valve200. In examples in which the pressure reader 660 includes an electronicdisplay, at step 1012, the pressure setting of the valve can bedisplayed and updated at periodic intervals, e.g., every two seconds. Ateither of step 1010 and step 1012, if the strength of the magnetic fieldis too low, the pressure reader 660 returns to step 1008, where thedisplay can indicate that the pressure reader is searching for asufficiently strong magnetic field.

A user can turn the pressure reader 660 on and off by pressing theon/off button on the pressure reader 660. In certain examples, after apredetermined time period, e.g., 360 seconds, the pressure reader 660automatically turns off.

According to certain aspects, a kit for setting a pressure in asurgically-implantable shunt valve 200 can include the pressure reader660 and the valve programmer 760. In other examples, a valve assembly100 can include an integrated valve programmer 760 and pressure reader660. In certain examples the pressure reader 660 and the valveprogrammer 760 can be provided to a user together as part of a kit, orthey can be provided separately from each other. In some examples, thekit can further includes a surgically-implantable programmable shuntvalve or valve assembly, such as a surgically-implantable shunt valve200 or valve assembly 100, or another surgically-implantableprogrammable shunt valve or valve assembly.

In certain circumstances where the indicator mechanism rotates with therotor 510 (e.g., where the indicator mechanism includes reference magnetelements 524 or certain ones of the rotor magnet elements, as discussedabove), external, non-programming magnetic fields, such as the fieldfrom an MRI, for example, can act upon the indicator/reference magnetsand undesirably induce a torque on the rotor 510. Accordingly, referringto FIG. 32 there is illustrated an example of the programmable valveshowing an alternate example of an indicator mechanism that can avoidthis occurrence. In the illustrated example, the indicator mechanismincludes a positioning magnet 550 that is attached to the rotor 510,very close to the center of the rotor. The positioning magnet 550 can beused to orient an indicator magnet 552. Thus, the indicator mechanismfurther includes the indicator magnet 552 that is not attached to therotor 510 and pivots freely on its own ruby bearing. In this example,both the positioning magnet 550 and the indicator magnet 552 have theshape of a ring and are diametrically magnetized. When the rotor 510moves, the positioning magnet 550 rotates with the rotor 510 andmagnetically attracts the indicator magnet 552 to make it rotate in thesame amount. In one embodiment, the positioning magnet 550 has a verysmall magnetic force, and therefore the influence of an MRI or othernon-programming magnetic field on the positioning magnet 550 will beinsufficient to overcome the cogging torque of the motor and cause therotor 510 to rotate. The magnetic force of the positioning magnet 550 isenough to attract the indicator magnet 552 to make it rotate in the sameamount, as discussed above. The side positioning magnets 553, 557, and559 discussed above may operate in a similar manner. In certain examplesthe indicator magnet 552 has a strong magnetic field, which can be readby a compass, Hall Sensor, or other magnet sensor 812 located outside ofthe patient's body (e.g., at a distance of 10 mm or more from the secondindicator magnet). For example, the indicator magnet can be a singlediametrically magnetized (i.e., having one north pole and one opposingsouth pole) magnet. The indicator magnet 552 may be influenced by anon-programming magnetic field, such as the field from an MRI; however,because the indicator magnet 552 can rotate freely on its own bearing,its movement does not cause the rotor 510 to rotate. When thenon-programming magnetic field is removed (e.g., after the MRI scan isfinished), the positioning magnet 550 will automatically re-orient theindicator magnet 552. By splitting the magnetic indicator mechanism intotwo separate magnets 550, 552, the valve 200 can have a magnet strongenough to be read from the outside and at the same time, a strongnon-programming magnetic field, such as the one produced by an MRI, willnot change the pressure setting of the valve 200 because the strongindicator magnet (552) is decoupled from the rotor 510.

In another embodiment, the positioning magnet 550 may be configured astwo small disk magnets with the north and south polarities axiallymagnetized, rather than as a diametrically magnetized single ringmagnet. In this case, for one of the two small disk magnets, the northis facing up towards the indicator magnet 552 and south is pointing awayfrom the indicator magnet 552. For the other of the two small diskmagnets, south is facing up towards the indicator magnet 552 and northfaces away from the indicator magnet 552. The principle of operation ofsuch a configuration is the same as discussed above with respect tocreating a local magnetic field for identifying the position of theindicator magnet 552. The use of two very small disk magnets toimplement the positioning magnet 550 may be preferred over a ring magnetin certain applications because this configuration may produce fewerartifacts in an image of the patient's body (as may be taken using anMRI or CT scan, for example).

The positioning magnet 550 can have a variety of other configurations aswell. For example, as discussed above with reference to FIGS. 28A-C, inother embodiments the positioning magnet 550 can be replaced with any ofthe arrangements of positioning magnets 553, 557, or 559, or similararrangements.

As discussed above, one limitation of conventional magneticallyadjustable valves is that verifying a pressure setting can entail theuse of an X-ray to detect a radiopaque marker on the implanted device.According to certain embodiments, an initial orientation of the rotor510 can be determined with respect to a reference, such as the housingand/or casing, using an indication mechanism as discussed above. Thepressure setting of the implanted valve 200 may be verified by placing acompass over the patient's head in the vicinity of the implanted valve200. The needle of the compass will align itself with the direction ofthe indicator magnet 552, as illustrated in FIG. 32, or the referencemagnet elements 524 a-c, as illustrated in FIG. 27, thus indicating theposition of the rotor 510. The physician is then able to determine thepressure setting of the valve 200 by considering the position of therotor 510 relative to the housing 202.

Accordingly, the position of the rotor 510 may be precisely determined,and thereby a precise setting of the valve's threshold opening pressuremay also be determined. In at least some embodiments, the rotor 510 isfree to rotate in at least one direction, beyond one full revolution,with the pressure settings repeating for each revolution. In thismanner, a position of the rotor 510 can uniquely identify a poppingpressure.

As discussed above, in certain embodiments the magnetic motor isintrinsically immune or highly resistant to external non-programmingmagnetic fields, including even strong magnetic fields associated withan MRI. However, in certain instances, further immunity (for example,very high or complete assurance that no movement of the rotor 510 willoccur) to very strong magnetic fields, such as those associated with anMRI, may be desired. Accordingly, in certain embodiments theprogrammable valve 200 may include a mechanical brake that preventsmovement of the rotor 510 when the brake is applied.

Referring to FIG. 33, there is illustrated a partial cross-sectionalview of one example of a magnetic motor including an example of amechanical brake according to one embodiment. In this example themechanical brake includes a brake spring 554 and a brake cylinder 556that can rotate about a central pivot 558. In one example the brakecylinder is made of a thermoplastic, such as Polyoxymethylene, forexample. The brake spring 554 may be made of metal, for example,stainless steel. In the example illustrated in FIG. 33, the brake spring544 is a disc with a shaped cut-out; however, the brake spring can havea variety of different shapes, some examples of which are discussedfurther below. The brake cylinder 556 includes a plurality of brakecylinder teeth 560 that are configured to engage with a correspondingplurality of motor teeth 562. When the brake is in the locked position,the brake cylinder teeth 560 engage with the motor teeth 562 to preventrotation of the rotor. When the brake is unlocked, the brake cylinderteeth 560 disengage with the motor teeth 562, allowing the rotor torotate freely responsive to the applied programming magnetic field, asdiscussed above.

According to certain embodiments, locking and unlocking of the brake isachieved using the second indicator magnet 552. As discussed above, incertain examples the indicator magnet 552 is a single magnet that isdiametrically magnetized. Accordingly, although small, the secondindicator magnet can have a relatively strong magnetic field that can beused to release the brake. As discussed above, the second indicatormagnet 552 is a freely rotating magnet, not tied to rotation of therotor 510. If an external magnet is placed close to the second indicatormagnet 552, the second indicator magnet will rotate to position itselfaccording to the magnetic field of the external magnet. In examples inwhich the second indicator magnet 552 is a diametrically magnetizedmagnet, if the external magnet is axially magnetized, it will not pullthe second indicator magnet towards itself, because one pole of thesecond indicator magnet will be attracted to the external magnet, whilethe other is repelled, and the two opposing forces balance one another.In contrast, if the external magnet is also diametrically magnetized,when it is placed close to the valve, the second indicator magnet 552will rotate to position itself according to the magnetic field of theexternal magnet, and then will be attracted to the external magnet.Thus, the second indicator magnet 552 will be pulled upwards towards theexternal magnet. This upward movement can be used to disengage thebrake, allowing rotation of the rotor 510 to program a pressure settingof the valve 200. When the external magnetic field is not applied, thebrake spring 554 presses the brake cylinder down, keeping the brakecylinder teeth 560 engaged with the motor teeth 562. Referring to FIG.34, in one example in which the central pivot 558 is circular, the brakecylinder 556 includes one or flat sections 563 on its interior wallsurrounding the central pivot such that the brake cylinder can only moveup and down and will not rotate. In other examples, other features orshapes can be employed to prevent rotation of the brake cylinder 556.FIG. 34 shows a schematic example of the motor 510 with the brakereleased.

Accordingly, in certain embodiments, the permanent magnet assembly 710of the valve programmer 700 includes a diametrically magnetized brakecontroller magnet that is used to disengage the brake when the valveprogrammer is placed in proximity to the valve 200 to program thepressure setting of the valve. FIG. 35 illustrates an example of apermanent magnet assembly 710 c of the valve programmer 700 including abrake controller magnet 740. The example shown in FIG. 35 is similar tothe permanent magnet assembly shown in FIG. 20A, and can be used toprogram a valve including a twelve-magnet rotor 510, as discussed above.

An example of operation of the motor and mechanical brake using anexample of the valve programmer 700 including the magnet assembly 710 cshown in FIG. 35 is discussed below with reference to FIGS. 36, 37A, and37B. FIG. 36 is a flow diagram of one example of a method of programmingthe valve 200. FIG. 37A illustrates a cross-sectional view of oneexample of the valve 200 showing aspects of the magnetic motor andmechanical brake with the brake in the locked position, and FIG. 37B isa corresponding view showing the brake in the unlocked position.

Referring to FIG. 36, in a first step 902 of programming a pressuresetting of the valve 200, a physician or other user selects the newpressure setting for the valve 200 directly on the valve programmer 700.In one example this can be achieved using a round display, such asillustrated in FIG. 11B, for example using a capacitive touch. In step904, the physician/user places the valve programmer 700 one or near thepatient's head in proximity to the implanted valve. As the start of theprocess, the brake is in the locked position, as shown for example inFIG. 37A. In some instances, it may be easier or more convenient for thephysician/user to first select the desired pressure setting of the valve(step 902) and the place the valve programmer 700 in proximity to thepatient's head (step 904); however, those skilled in the art willappreciate that steps 902 and 904 may be performed in the reverse order.In step 906 the brake in the valve 200 is released so that the valveprogrammer 700 can act on the magnetic motor to program the selectedpressure setting. In one embodiment of the valve programmer 700including the permanent magnet assembly 710 c, the central diametricallymagnetized brake controller magnet 740 is in a higher position than theother four magnets 722, 724, 726 and 728. For example, the brakecontroller magnet 740 can be held in this position by a spring pushingup. The physician/user can press down on the brake controller magnet 740until it touches the skin on top of the implanted valve 200, forexample. When the brake controller magnet 740 is touching the skin, itunlocks the brake by attracting the second indicator magnet 552, asdiscussed above and as shown in FIG. 37B, for example. In step 908 thevalve programmer 700 is used to program the selected pressure setting ofthe valve 200 by magnetizing the stator 528 to cause rotation of therotor 510 to the position corresponding to the selected pressuresetting, as discussed above. In one example the valve programmer 700 caninclude a programming “on” switch that can be activated after the brakeis released to allow programming to begin. The “on” switch can be builtinto permanent magnet assembly 710, and in particular, into the brakerelease mechanism. For example, the physician/user can push downslightly harder on the brake controller magnet 740 to trigger the switchto start the programming. In one example the switch must remain pressedwhile the programming is taking place. After the programming has beencompleted, an indication of completion can be provided to thephysician/use, for example, an acoustic feedback can be heard. At thisindication, the brake controller magnet 740 is released by thephysician/user, and pushed back up into its inactive position by thespring. Upon removal of the magnetic field from the brake controllermagnet 740, and the second indicator magnet 552 is no longer attractedupwards, and returns to its neutral position, and as a result, the brakecylinder 556 moves downward (pressed down by the brake spring 554),causing the brake cylinder teeth 560 to re-engage with the motor teeth562 and lock the rotor 510 in the programmed position (step 910). Thevalve programmer 700 can then be removed from the patient's head (step912).

FIG. 38 illustrates another example of a magnet assembly 710 d that canbe used in the valve programmer 700 to program a valve including aten-magnet rotor 510, for example. In this example, the two permanentmagnets 732, 734 of the example permanent magnet assembly 710 b shown inFIG. 20B have been replaced with a single diametrically magnetizedcontroller magnet 742 which is used to both release the brake andprogram the pressure setting of the valve 200 as discussed above.

FIG. 39 is a flow diagram of one example of a method of programming thevalve 200 having a ten-magnet rotor 510 and using a valve programmer 200that includes an example of the magnet assembly 710 d shown in FIG. 38.As in the example discussed above, in a first step 902 of theprogramming sequence, the physician/user selects the new pressuresetting for the valve 200 directly on the valve programmer 700. Thephysician/user can then place the valve programmer 700 in proximity tothe implanted valve (step 914), which automatically releases the brakedue to the presence of the diametrically magnetized controller magnet742. In step 916 the physician/user actuates the programming sequence.This can be achieved by pressing a “start” button on the valveprogrammer 200, for example. In step 918 the valve programmer 700 isused to program the selected pressure setting of the valve 200 bymagnetizing the stator 528 to cause rotation of the rotor 510 to theposition corresponding to the selected pressure setting, as discussedabove. When the programming sequence is complete, and the selectedpressure setting has been reached, the programmer may signal completionof the programming sequence (step 920) using, for example, an acousticor visual indicator (e.g., a beep, displaying a light or flashing lightof a particular color, etc.). After the programming has been completedand the signal is heard/seen, the physician/user can remove the valveprogrammer from proximity to the patient's head, thereby automaticallyengaging the brake (step 922).

As shown in FIGS. 37A and 37B, in one embodiment the motor includes apair of ruby bearings 564 that allow the second indicator magnet 552 torotate with respect to the brake cylinder 556 for the purpose ofindicating the position of the rotor 510 and the corresponding pressuresetting of the valve 200, as discussed above. In one example the secondindicator magnet 552 is contained in a casing that rotates on the rubybearings 564.

As will be appreciated by those skilled in the art, given the benefit ofthis disclosure, the brake mechanism and its components can have avariety of different structural forms and be implemented in combinationwith any of various embodiments of the magnetic motor and itscomponents. In the example shown in FIGS. 37A and 37B, the magneticindicator mechanism includes the first indicator magnet(s) 550 thatcooperate with the second indicator magnet 552. However, the brakemechanism can also be implemented with valve configurations in which oneor more slightly “taller” rotor magnet elements 512, as discussed above,are used in combination with the second indicator magnet 552 forposition sensing instead of the first indicator magnet(s) 550. In theexample shown in FIG. 33, the brake cylinder teeth 560 and the motorteeth 562 are shown close to the central pivot 558, to the “inside” ofand “below” the second indicator magnet 552. However, a wide variety ofthe other configurations can be implemented. For example, referring toFIG. 40 there is illustrated another embodiment in which the brakecylinder 556 spans the second indicator magnet 552 and the brakecylinder teeth 560 and corresponding motor teeth 562 are positioned tothe “outside” of the second indicator magnet 552.

In the examples shown in FIGS. 33, 34, 37A-B, and 40, the brake cylinder556 includes brake cylinder teeth 560 that engage the motor teeth 562 tolock the rotor 510 in position, as discussed above. According to anotherembodiment, the brake spring 554 can include features that engage withthe motor teeth 562, thereby removing the need for the brake cylinderteeth 560. For example, referring to FIG. 41 there is illustrated apartial cross-sectional perspective view of another embodiment of theprogrammable valve 200 in which the brake spring 554 includes a pair ofarms 566 each having a projection 566 a configured to engage with themotor teeth 562 to lock the rotor 510. In this example the motor teeth562 are positioned around a circumference of the rotor casing 514. FIG.42 is a plan view of one example of the embodiment shown in FIG. 41 inwhich the rotor 510 includes twelve rotor magnet elements 512. FIG. 43is a plan view of another example of a similar embodiment to that shownin FIG. 41 in which the rotor 510 includes ten rotor magnet elements.FIG. 44A is a cross-sectional view taken along line A-A in FIG. 42, andFIG. 44B is another cross-sectional view taken along line B-B in FIG.42. In one example, in which the rotor includes twelve rotor magnetelements 512, the plurality of motor teeth 562 includes 24 motor teeth,such that the rotor can be locked into each position corresponding torotation step of one half-width of a rotor magnet element. However,different configurations can include different numbers of motor teeth562. In the examples shown in FIGS. 41 and 42, the brake spring 554includes two arms 566, and each arm includes a projection 566 a at itstip, the projection being thinner/narrower than the body of the arm 566and configured to fit between a pair of adjacent motor teeth 562 whenthe brake is in the locked position. However, as will be appreciated bythose skilled in the art, given the benefit of this disclosure, avariety of different configurations can be implemented, provided onlythat the brake spring 554 includes one or more features that areconfigured to engage with the motor teeth 562 to prevent rotation of therotor 510. For example, the brake spring 554 shown in FIG. 43 includesarms 566 that are more uniform in width, lacking the defined projection566 a. Referring to FIG. 45, in another embodiment the brake spring 554includes four arms 566, rather than two, positioned around a centralring portion 568, and the arms are more uniform in width, similar to theexample shown in FIG. 43, rather than having the narrower endprojections 566 a illustrated in FIG. 40. In the examples shown in FIGS.43 and 45, the width of the arms 566 and spacing between adjacent motorteeth 562 can be selected such that the arms can fit between adjacentmotor teeth to lock to rotor 510 in position and prevent its rotation.

Referring to FIGS. 46A and 46B, embodiments of the magnetic motor thatincorporate a brake mechanism using the brake spring 554 to engage themotor teeth 562 can be operated in the same manner as discussed aboveusing a brake controller magnet 740 or 742 to unlock or release thebrake. In one example, the motor teeth 562 are positioned on the topcircumference of the rotor casing 514, as shown in FIG. 46A, and in thelocked position, the spring 554 rests such that the arms 566 are locatedbetween adjacent motor teeth such that rotation of the rotor 510 isthereby prevented. The brake spring 554 can be supported by the topcover 202 a of the valve. As discussed above, and as shown in FIG. 46B,when the diametrically magnetized brake controller magnet 740 or 742 isplaced above the valve 200, it will attract the second indicator magnet552 and push up the brake spring 554, thereby unlocking the rotor 510 sothat it is free to rotate. As shown in FIGS. 46A and 46B, in one examplethe second indicator magnet 552 is located in a casing 570 that includesa casing projection 572. When the second indicator magnet 552 is pulledupwards by the brake controller magnet 740 or 742, the casing projection572 presses against the spring arms 566, lifting the arms above themotor teeth 562 so that the rotor 510 can rotate. When the brakecontroller magnet 740 or 742 is removed, the brake spring 554 drops backdown such that the arms 566 again rest between adjacent motor teeth 562,as shown in FIG. 46A.

FIGS. 47A and 47B show another example of a programmable valve 200including a ten-magnet rotor 510, also showing an example of the brakemechanism. FIG. 47A is a plan view of the programmable valve 200, andFIG. 47B is a cross-sectional view taken along line A-A in FIG. 47A.

FIG. 48 shows another example of a programmable valve 200 a including astepper motor, a brake mechanism, and an indicator magnet assemblyaccording to certain embodiments. In this example the cam 212 has aninclined surface 213 and the spring 409 includes a central arm 409 jflanked by two parallel arms 409 k. The central arm 409 j is acantilevered arm with a free end 409 h resting against the valve element208, and the two parallel arms 409 k are fixed to the underside of apivot point 407. The relationship between the position of the cam 212and the tension of the spring 409 is dependent on the location of thepivot point 407, the point of the contact between the spring 409 and thecam 212, and the point of contact between the cantilevered arm 409 g andthe valve element 208. Depending on these relationships, when the cam212 is at its highest position, the cantilevered arm 409 g can be pushedtoward the valve element 208, or alternatively, the cantilevered arm 409g can be pushed away from the valve element 208. In the configurationdepicted in FIG. 48, when the cam 212 is at its highest position (or itshighest level of incline) against the spring 409, the tension of thespring 409 is the greatest and tends to push the cantilevered arm 409 gin the direction toward the valve element 208. The valve 200 a of FIG.48 incorporates brake teeth 562 that engage a brake spring 554, asdiscussed above, to prevent unwanted changes to the pressure setting ofthe valve 200 a when exposed to a magnetic field (other than aprogramming field).

Embodiments of the valve assembly 100 may be implanted in a patientusing well-described surgical procedures. The pressure setting of thevalve 200 can be adjusted to a desired pressure setting prior tosurgical implantation. In one aspect, the working pressure can be set tobe approximately equal to the patient's ventricular CSF pressure suchthat no pressure change occurs after the surgery. After the patientrecovers from surgery, the pressure setting can be adjusted as desired.For example, in a patient suffering from NPH, the pressure setting canbe decreased in order to initiate a reduction in the size of theventricles. Additional adjustments in the pressure setting canadditionally be made. For example, once the size of the ventricles hadbeen reduced sufficiently, the pressure setting of the valve can beincreased. As will be appreciated, use of the implanted valve 200permits the pressure setting of the valve 200 to be externally adjustedas needed over the course of treating the patient.

In certain embodiments, a method of treating hydrocephalus includesimplanting an embodiment of the valve assembly 100 having a ventricularcatheter 120 within a ventricular cavity of the patient's brain anddistal catheter connected to the connector 140 installed at a remotelocation in the patient's body where the fluid is to drain. Remotelocations of the body where CSF drains include, for example, the rightatrium of the heart and the peritoneum.

In addition to hydrocephalus, there are several other conditionsassociated with the accumulation of excess fluid and that can be treatedby draining the fluid using a suitably-designed inflow catheter intoanother part of the body. Such conditions include, for example, chronicpericardial effusions, chronic pulmonary effusion, pulmonary edema,ascites, and glaucoma in the eye. It is contemplated that embodiments ofthe programmable valve 200 may be used in the treatment of theseconditions.

The pressure settings of the valves described herein can be adjusted inmany discrete steps or increments, or continuously over a predeterminedrange, as discussed above. Embodiments of the valves described hereinmay vary in pressure from a low pressure, for example, 10 mm H₂O, to ahigh pressure, for example 400 mm H₂O. Most conventional valves onlyhave pressures as high as 200 mm H₂O and can only be adjusted inrelatively high increments between each pressure setting.

Having described above several aspects of at least one embodiment, it isto be appreciated various alterations, modifications, and improvementswill readily occur to those skilled in the art. Such alterations,modifications, and improvements are intended to be part of thisdisclosure and are intended to be within the scope of the invention.Accordingly, the foregoing description and drawings are by way ofexample only, and the scope of the invention should be determined fromproper construction of the appended claims, and their equivalents.

What is claimed is:
 1. A system comprising: an externally programmablesurgically-implantable shunt valve assembly including: a housing, anexterior of the housing being formed of a physiologically compatiblematerial; a magnetically operable motor disposed within the housing, themagnetically operable motor including a stator and a rotor configured torotate relative to the stator responsive to a changing magnetic polarityof the stator induced by an external magnetic field, the rotor includinga rotor casing and a plurality of rotor permanent magnet elementsdisposed in a ring within the rotor casing and arranged with alternatingmagnetic polarities, a number of the rotor permanent magnet elementsbeing such that radially opposing ones of the plurality of rotorpermanent magnet elements have the same magnetic polarity, rotation ofthe rotor relative to the stator producing a selected pressure settingof the shunt valve assembly; an inlet port positioned between the rotorcasing and the exterior of the housing, the inlet port terminating atits rotor casing end in a valve seat; a spring; a valve element biasedagainst the valve seat by the spring, the valve element and the valveseat together forming an aperture; and an outlet port positioned betweenthe rotor casing and the exterior of the housing, the shunt valveassembly configured such that the aperture opens when a pressure of thefluid in the inlet port exceeds the selected pressure setting of theshunt valve assembly so as to vent fluid through the aperture into theoutlet port; a non-implantable transmitter head including a magnetassembly configured to produce the external magnetic field to induce therotation of the rotor relative to the stator; and a control devicecoupled to the transmitter head and configured to provide a signal tothe transmitter head to control the transmitter head to produce theexternal magnetic field so as to set the pressure setting of the shuntvalve assembly to the selected pressure setting.
 2. The system of claim1 wherein the control device includes a user interface configured toreceive an input from the user that sets the selected pressure settingof the shunt valve assembly.
 3. The system of claim 1 wherein the magnetassembly includes a plurality of electromagnets configured to producepulses of the external magnetic field.
 4. The system of claim 1 whereinthe magnet assembly includes a rotatable magnet guide and a plurality ofpermanent magnets mounted to the rotatable magnet guide, rotation of therotatable magnet guide inducing the changing magnetic polarity of thestator when the non-implantable transmitter head is in proximity to theimplantable shunt valve assembly.
 5. The system of claim 4 wherein theplurality of permanent magnets in the magnet assembly includes at leastone pair of opposing permanent magnets of north and south polarity. 6.The system of claim 4 wherein the control device includes a motorconfigured to actuate rotation of the rotatable magnet guide.
 7. Thesystem of claim 1 wherein the control device further includes a detectorconfigured to determine a position of the rotor indicative of thepressure setting of the valve assembly.
 8. The system of claim 1 furthercomprising a magnetic detector configured to determine a position of therotor indicative of the pressure setting of the valve assembly.
 9. Thesystem of claim 1 wherein the magnetically operable motor furtherincludes first and second position indicator magnets that allow thecontrol device to magnetically determine a position of the rotor. 10.The system of claim 9 wherein the first position indicator magnet iscoupled to the rotor and rotates with the rotor, and wherein the secondposition indicator magnet rotates about the central axis of rotation ona bearing independent of rotation of the rotor.
 11. The system of claim10 wherein the second indicator magnet is a diametrically magnetizedring-shaped magnet.
 12. The system of claim 11 wherein the magneticallyoperable motor further includes a mechanical brake magnetically operablebetween a locked position and an unlocked position and configured, inthe locked position, to prevent rotation of the rotor.
 13. The system ofclaim 12 wherein the rotor casing includes a plurality of motor teethdisposed on an upper surface thereof, and wherein the mechanical brakeincludes a brake spring having at least one arm configured to restbetween adjacent ones of the plurality of motor teeth when themechanical brake is in the locked position.
 14. A system comprising: anexternally programmable surgically-implantable shunt valve assemblyincluding a housing, a magnetically operable motor disposed within thehousing, the magnetically operable motor being configured to produce aselected pressure setting of the shunt valve assembly, an inlet portformed in the housing, the inlet port including a valve seat, a valveelement biased against the valve seat, the valve element and the valveseat together forming an aperture, and an outlet port formed in thehousing, wherein the shunt valve assembly is configured such that theaperture opens when a pressure of the fluid in the inlet port exceedsthe selected pressure setting of the shunt valve assembly so as to ventfluid through the aperture into the outlet port; a non-implantabletransmitter head including a magnet assembly configured to produce anexternal magnetic field to set the pressure setting of the shunt valveassembly to the selected pressure setting; and a control device coupledto the transmitter head and configured to provide a signal to thetransmitter head to control the transmitter head to produce the externalmagnetic field so as to set the pressure setting of the shunt valveassembly to the selected pressure setting.
 15. The system of claim 14wherein the control device includes a user interface configured toreceive an input from the user that sets the selected pressure settingof the shunt valve assembly.
 16. The system of claim 14 wherein themagnet assembly includes a plurality of electromagnets configured toproduce pulses of the external magnetic field.
 17. The system of claim14 wherein the magnet assembly includes a rotatable magnet guide and aplurality of permanent magnets mounted to the rotatable magnet guide,rotation of the rotatable magnet guide inducing the changing magneticpolarity of a stator of the magnetically operable motor when thenon-implantable transmitter head is in proximity to the implantableshunt valve assembly.
 18. The system of claim 14 wherein the controldevice further includes a detector configured to determine a position ofa rotor of the magnetically operable motor indicative of the pressuresetting of the valve assembly.
 19. The system of claim 14 furthercomprising a magnetic detector configured to determine a position of arotor of the magnetically operable motor indicative of the pressuresetting of the valve assembly.
 20. The system of claim 14 wherein themagnetically operable motor further includes a mechanical brakemagnetically operable between a locked position and an unlocked positionand configured, in the locked position, to prevent rotation of a rotorof the magnetically operable motor.